Viral IL-10 gene transfer decreases inflammation and cell adhesion molecule expression in a rat model of venous thrombosis

Protective Role of Endothelial SIRT1 in Deep Vein Thrombosis and Hypoxia-induced Endothelial Dysfunction Mediated by NF-κB Deacetylation

Venous hypoxia is considered as the major pathogenetic mechanism linking blood flow stagnancy with deep vein thrombosis (DVT). Our previous study showed that activating SIRT1 may attenuate inferior vena cava (IVC) stenosis-induced DVT in rats. This study was aimed to investigate the role of endothelial SIRT1 in DVT and hypoxia-induced endothelial dysfunction as well as the underlying mechanism. Protein profiling of IVCs and blood plasma of DVT rats induced by IVC stenosis was analysed by 4D Label free proteomics analysis. To verify the independent role of SIRT1 in DVT and oxygen-glucose deprivation (OGD)-induced endothelial dysfunction, SIRT1 specific activator SRT1720 and SIRT1 knockdown in both local IVCs and endothelial cells were employed. Moreover, the role of the NF-κB were investigated using NF-κB inhibitor caffeic acid phenethyl ester (CAPE). SRT1720 significantly inhibited thrombus burden, leukocytes infiltration, protein expressions of cell adhesion molecules and chemokines, as well as acetylation level of NF-κB/p65 in wild DVT rats, while these protective effects of SRT1720 were abolished in rats with SIRT1 knockdown in local IVCs. In vitro, SRT1720 protected endothelial cells against OGD-induced dysfunction characterized with enhanced adhesion of monocytes as well as the protein expressions of cell adhesion molecules and chemokines, whereas these protective effects of SRT1720 were vanished by SIRT1 stable knockdown. Furthermore, CAPE attenuated endothelial cell dysfunction and abolished these effects of SIRT1 knockdown. Collectively, these data suggested that endothelial SIRT1 plays an independent role in ameliorating hypoxia-induced endothelial dysfunction and thrombotic inflammation in DVT, and this effect is mediated by NF-κB deacetylation.

The diverse roles of macrophages in metabolic inflammation and its resolution

Macrophages are one of the most functionally diverse immune cells, indispensable to maintain tissue integrity and metabolic health. Macrophages perform a myriad of functions ranging from promoting inflammation, through inflammation resolution to restoring and maintaining tissue homeostasis. Metabolic diseases encompass a growing list of diseases which develop from a mix of genetics and environmental cues leading to metabolic dysregulation and subsequent inflammation. In this review, we summarize the contributions of macrophages to four metabolic conditions-insulin resistance and adipose tissue inflammation, atherosclerosis, non-alcoholic fatty liver disease and neurodegeneration. The role of macrophages is complex, yet they hold great promise as potential therapies to address these growing health concerns.

Pilot study of peripheral blood chemokines as biomarkers for atrial fibrillation-related thromboembolism and bleeding in elderly patients

Background

The scoring systems currently used to identify the potential for thrombosis and bleeding events in high-risk atrial fibrillation patients have certain limitations. The aim of this pilot study was to identify inflammatory chemokines with potential utility as sensitive biomarkers for the risk of thrombosis and bleeding in elderly patients with non-valvular atrial fibrillation.

Methods

From January 1, 2014, to December 31, 2017, 200 consecutive elderly patients with atrial fibrillation (average age: 87.6 ± 7.7 years) were enrolled and followed up for 2 years to observe thromboembolic (arterial and venous) and bleeding events. Serum was collected upon enrollment, and the baseline levels of 27 chemokines were analyzed. During the 2-year follow-up, 12 patients were lost to follow-up. Among the 188 patients, there were 32 cases (17.0%) of AF-related thrombosis, 36 cases (19.1%) of arterial thrombosis, and 35 cases (18.6%) of major bleeding events.

Results

Among 188 patients, 30 patients without clinical events (control group), 23 with arterial thrombosis, 15 with atrial fibrillation-related venous thromboembolism, and 12 with major bleeding were selected and randomly matched to compare chemokine levels. The baseline levels of interleukin-6, interleukin-10, vascular cell adhesion molecule-1, chemokine C-C-motif ligand, B-lymphocyte chemoattractant 1, interleukin-4, E-selectin, fractalkine, C-X-C motif chemokine 12, and granulocyte chemotactic protein 2 were found to differ statistically among the four groups (p < 0.05). Compared with that in the control group, the level of interleukin-4 in patients with atrial fibrillation-related thrombosis, arterial thrombosis, or major bleeding increased by 53-fold (0.53 vs. 0.01 pg/ml), 17-fold (0.17 vs. 0.01 pg/ml), and 19-fold (0.19 vs. 0.01 pg/ml), respectively. Compared with that in the control group, the level of interleukin-6 in patients with arterial thrombosis increased by six-fold (39.78 vs. 4.98 pg/ml).

Conclusions

Among elderly patients with atrial fibrillation at high risk of thromboembolism and bleeding, the baseline levels of interleukin-6, interleukin-4, and E-selectin were significantly increased in those that experienced thrombosis and bleeding events during the 2-year follow-up, indicating that these chemokines may serve as potential biomarkers for an increased risk of thrombosis and bleeding in this population.

Clinical trial registration number

ChiCTR-OCH-13003479.

Inflammation in Cerebral Venous Thrombosis

Cerebral venous thrombosis (CVT) is a rare form of cerebrovascular disease that impairs people's wellbeing and quality of life. Inflammation is considered to play an important role in CVT initiation and progression. Several studies have reported the important role of leukocytes, proinflammatory cytokines, and adherence molecules in the CVT-related inflammatory process. Moreover, inflammatory factors exacerbate CVT-induced brain tissue injury leading to poor prognosis. Based on clinical observations, emerging evidence shows that peripheral blood inflammatory biomarkers-especially neutrophil-to-lymphocyte ratio (NLR) and lymphocyte count-are correlated with CVT [mean difference (MD) (95%CI), 0.74 (0.11, 1.38), p = 0.02 and -0.29 (-0.51, -0.06), p = 0.01, respectively]. Moreover, increased NLR and systemic immune-inflammation index (SII) portend poor patient outcomes. Evidence accumulated since the outbreak of coronavirus disease-19 (COVID-19) indicates that COVID-19 infection and COVID-19 vaccine can induce CVT through inflammatory reactions. Given the poor understanding of the association between inflammation and CVT, many conundrums remain unsolved. Further investigations are needed to elucidate the exact relationship between inflammation and CVT in the future.

The effects of exercise and active assisted cycle ergometry in post-operative total knee arthroplasty patients - a randomized controlled trial

Purpose

The purpose of this study was to examine the effect of the use of an active assisted cycle ergometer as an adjunct to post-operative treatment following total knee arthroplasty.

Method

A total of 55 participants aged 50–80 years who had undergone unilateral total knee arthroplasty were randomly assigned to either the control group (standard of care) or the active assisted cycle ergometer (AACE) group. The effect on patient motivation, blood biomarkers, and knee pain, function, range of motion (ROM), strength, and swelling was examined. Qualitative feedback was also obtained post-operatively.

Results

Although there was no statistically significant difference in the standard of care compared to the AACE group, there was a trend for a greater reduction in knee pain on the visual analog scale, improved Lower Extremity Functional Scale scores, and knee extension ROM and strength. A greater percentage of the experimental group demonstrated higher motivation. There was no significant difference in swelling or blood biomarker measures. Qualitative feedback from the AACE group post-operatively was also positive.

Conclusions

The use of an AACE protocol as an adjunct to total knee arthroplasty rehabilitation may improve post-operative clinical outcomes. This study has been registered at clinicaltrials.gov (identifier NCT02265523, Oct 16 2014). Level of evidence: Level 1 – randomized controlled trial. Further research with a larger sample size is needed to confirm the benefits of the ergometer use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-021-00363-w.

Association between chronic osteomyelitis and deep-vein thrombosis

Studies on the association between chronic osteomyelitis and deep vein thrombosis (DVT) and pulmonary thromboembolism (PE) are scarce. The aim of this study was to analyse a nationwide population-based database for association between DVT or PE after a diagnosis of chronic osteomyelitis. This nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Database from 1998 to 2008, with a follow-up period extending to the end of 2010. We identified patients with chronic osteomyelitis using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. The patients with chronic osteomyelitis and comparison controls were selected by 1:1 matching on a propensity score. The propensity score was calculated by a logistic regression to estimate the probability of the treatment assignment given the baseline variables including age, sex, and Charlson comorbidity index score. We analysed the risks of DVT and PE by using Cox proportional hazards regression models, including sex, age, and comorbidities. In total, 24,335 chronic osteomyelitis patients and 24,335 controls were enrolled in the study. The risk of developing DVT was 2.49-fold in patients with chronic osteomyelitis compared with the comparison cohort, after adjusting for age, sex, and comorbidities. The multiplicative increased risks of DVT were also significant in patients with chronic osteomyelitis with any comorbidity. In conclusion, physicians should consider chronic osteomyelitis in their evaluation of risk factors for DVT.

Interleukin-35 Inhibits Endothelial Cell Activation by Suppressing MAPK-AP-1 Pathway

Vascular response is an essential pathological mechanism underlying various inflammatory diseases. This study determines whether IL-35, a novel responsive anti-inflammatory cytokine, inhibits vascular response in acute inflammation. Using a mouse model of LPS-induced acute inflammation and plasma samples from sepsis patients, we found that IL-35 was induced in the plasma of mice after LPS injection as well as in the plasma of sepsis patients. In addition, IL-35 decreased LPS-induced proinflammatory cytokines and chemokines in the plasma of mice. Furthermore, IL-35 inhibited leukocyte adhesion to the endothelium in the vessels of lung and cremaster muscle and decreased the numbers of inflammatory cells in bronchoalveolar lavage fluid. Mechanistically, IL-35 inhibited the LPS-induced up-regulation of endothelial cell (EC) adhesion molecule VCAM-1 through IL-35 receptors gp130 and IL-12Rβ2 via inhibition of the MAPK-activator protein-1 (AP-1) signaling pathway. We also found that IL-27, which shares the EBI3 subunit with IL-35, promoted LPS-induced VCAM-1 in human aortic ECs and that EBI3-deficient mice had similar vascular response to LPS when compared with that of WT mice. These results demonstrated for the first time that inflammation-induced IL-35 inhibits LPS-induced EC activation by suppressing MAPK-AP1-mediated VCAM-1 expression and attenuates LPS-induced secretion of proinflammatory cytokines/chemokines. Our results provide insight into the control of vascular inflammation by IL-35 and suggest that IL-35 is an attractive novel therapeutic reagent for sepsis and cardiovascular diseases.

Defibrotide: properties and clinical use of an old/new drug

The drug named defibrotide (DFT) has been studied for many years. It has been shown to possess many activities: profibrinolytic, antithrombotic-thrombolytic, antiischemic (heart, liver, kidney, skin, brain), antishock, antiatherosclerotic, antirejection and anti-angiogenic. The previously displayed activities, as antithrombotic, profibrinolytic and anti-inflammatory, suggested its use in vascular disorders, as in the treatment of peripheral obliterative arterial disease and in thrombophlebitis. Some years after, the use of DFT in hepatic veno-occlusive disease has been also proposed. Even if DFT was considered for long time a multi-target drug, now it could be considered on the whole as a drug able to protect endothelium against activation. The present work reviews the more important experimental and clinical studies performed to detect DFT effects.

Inflammatory cytokines in vascular dysfunction and vascular disease

The vascular inflammatory response involves complex interaction between inflammatory cells (neutrophils, lymphocytes, monocytes, macrophages), endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and extracellular matrix (ECM). Vascular injury is associated with increased expression of adhesion molecules by ECs and recruitment of inflammatory cells, growth factors, and cytokines, with consequent effects on ECs, VSMCs and ECM. Cytokines include tumor necrosis factors, interleukins, lymphokines, monokines, interferons, colony stimulating factors, and transforming growth factors. Cytokines are produced by macrophages, T-cells and monocytes, as well as platelets, ECs and VSMCs. Circulating cytokines interact with specific receptors on various cell types and activate JAK-STAT, NF-kappaB, and Smad signaling pathways leading to an inflammatory response involving cell adhesion, permeability and apoptosis. Cytokines also interact with mitochondria to increase the production of reactive oxygen species. Cytokine-induced activation of these pathways in ECs modifies the production/activity of vasodilatory mediators such as nitric oxide, prostacyclin, endothelium-derived hyperpolarizing factor, and bradykinin, as well as vasoconstrictive mediators such as endothelin and angiotensin II. Cytokines interact with VSMCs to activate Ca(2+), protein kinase C, Rho-kinase, and MAPK pathways, which promote cell growth and migration, and VSM reactivity. Cytokines also interact with integrins and matrix metalloproteinases (MMPs) and modify ECM composition. Persistent increases in cytokines are associated with vascular dysfunction and vascular disease such as atherosclerosis, abdominal aortic aneurysm, varicose veins and hypertension. Genetic and pharmacological tools to decrease the production of cytokines or to diminish their effects using cytokine antagonists could provide new approaches in the management of inflammatory vascular disease.

Thrombus resolution and vein wall injury: dependence on chemokines and leukocytes

Chronic venous insufficiency resulting in post-thrombotic syndrome occurs commonly after acute deep vein thrombosis, and is a prevalent cause of vascular disease morbidity in the community. Therefore, a better understanding of the pathophysiologic mechanisms that promote the development of chronic venous insufficiency could lead to novel approaches to interrupt the natural history and prevent post-thrombotic syndrome. In this paper, we will review the evidence that venous thrombus resolution is an inflammatory process that is dependent on chemokines and leukocytes.

Interleukin 10 gene promoter polymorphisms in women with pregnancy loss: preferential association with embryonic wastage

Interleukin 10 (IL10) is associated with maternal immunotolerance. IL10 also down-regulates decidual cell tissue factor expression, the main molecule triggering coagulation activation: this antithrombotic effect may protect the umbilicoplacental vasculature from the 10th wk of gestation onward. IL10 down-regulation may thus dispose to early pregnancy loss (PL) due to maternal immunotolerance defect or late pregnancy failure due to placental vascular insufficiency. IL10 gene promoter polymorphisms associated with cytokine down-regulation may help to identify the actual and probable mechanisms of IL10 modulation in pregnancy outcomes. We investigated the following four IL10 promoter polymorphisms associated with IL10 down-regulation: two single-nucleotide polymorphisms rs1800871 and rs1800872 and two polymorphic CA repeat microsatellites IL10 X78437.2:g8134CA(14_29) and IL10 X78437.2:g.5325CA(11_15). Each microsatellite was analyzed as a biallelic polymorphism. Based on a review of the literature, we define a short allele and a long allele for each microsatellite. We compared their frequencies in early PL occurring before 10 wk of amenorrhea (n = 342) and in PL occurring later on (n = 123). The mutated alleles rs1800871T (odds ratio, 3.083; 95% confidence interval, 1.984-4.792) and rs1800872A (odds ratio, 3.013; 95% confidence interval, 1.924-4.719) were associated with early PL. The haplotype rs1800872A/rs1800871T/X78437.2:g.8134CA[14_25]/X78437.2:g.5325CA[11_13], which includes the two mutated alleles, was significantly associated with the risk of early PL in a dose-dependent manner. Positivity for one haplotype was significantly associated with a 5.6-fold increase in the risk of early pregnancy failure, and positivity for two haplotypes was associated with an 8-fold increase in risk. In women with PL, some polymorphisms of the IL10 gene promoter seem to be constitutional risk factors for early (embryonic) pregnancy failure.

Systemic delivery of IL-10 by an AAV vector prevents vascular remodeling and end-organ damage in stroke-prone spontaneously hypertensive rat

Interleukin-10 (IL-10) ameliorates various T-helper type 1 cell-mediated chronic inflammatory diseases. Although the therapeutic benefits of IL-10 include antiatherosclerotic effects, pathophysiological effects of IL-10 on vascular remodeling in hypertension have not yet been elucidated. These studies were designed to determine whether sustained IL-10 expression, mediated by an adeno-associated virus (AAV) vector, prevents vascular remodeling and target-organ damage in the stroke-prone spontaneously hypertensive rat (SHR-SP)-an animal model of malignant hypertension. A single intramuscular injection of an AAV1 vector encoding rat IL-10 introduced long-term IL-10 expression. These IL-10-transduced rats had decreased stroke episodes and proteinuria, resulting in improved survival. Histological examination revealed a reduced level of deleterious vascular remodeling of resistance vessels in the brain and kidney of these rats. Immunohistochemical analysis indicated that IL-10 inhibited the enhanced renal transforming growth factor-beta expression and perivascular infiltration of monocytes/macrophages and nuclear factor-kappaB-positive cells normally observed in the SHR-SP. Four weeks after IL-10 vector injection, systolic blood pressure significantly decreased and this effect persisted for several months. Overall, AAV vector-mediated systemic IL-10 expression prevented vascular remodeling and inflammatory lesions of target organs in the SHR-SP. This approach provides significant insights into the prevention strategy of disease onset with unknown genetic predisposition or intractable polygenic disorders.

Adenovirus viral interleukin-10 inhibits adhesion molecule expressions induced by hypoxia/reoxygenation in cerebrovascular endothelial cells

AIM

To investigate the effects of recombinant adenovirus encoding viral interleukin-10 (vIL-10), a potent anti-inflammatory cytokine, on adhesion molecule expressions and the adhesion rates of leukocytes to endothelial cells in cerebrovascular endothelial cells injured by hypoxia/reoxygenation (H/R).

METHODS

A recombinant adenovirus expressing vIL-10 (Ad/vIL-10 (or the green fluorescent protein (Ad/GFP) gene was constructed. A cerebrovascular endothelial cell line bEnd.3 was pretreated with a different multiplicity of infection (MOI) of Ad/vIL-10 or Ad/GFP and then exposed to hypoxia for 9 h followed by reoxygenation for 12 h. The culture supernatants were tested for the expression of vIL-10 and endogenous murine IL-10 (mIL-10) by ELISA. The effects of Ad/vIL-10 on monocyte-endothelial cell adhesion were represented as the adhesion rate. Subsequently, the expressions of intercellular adhesion molecule 1(ICAM-1) and vascular cell adhesion molecule 1( VCAM-1) in the endothelial cells after treatment with Ad/vIL-10 and H/R were analyzed by Western blotting and real-time PCR.

RESULTS

vIL-10 was expressed in cultured bEnd.3 after Ad/vIL-10 transfection and was significantly increased by H/R. Ad/vIL-10 or Ad/GFP did not affect the mIL-10 level. H/R increased the mIL-10 expression, but insignificantly. Monocyte- endothelial cell adhesion induced by H/R was significantly inhibited by pretreatment with Ad/vIL-10(MOI:80). ICAM-1, and VCAM-1 in bEnd.3 and were significantly increased after H/R, while pretreatment with Ad/vIL-10 (MOI: 80) significantly inhibited their expressions. Ad/GFP did not markedly affect monocyte- endothelial adhesion and the expressions of ICAM-1 and VCAM-1 induced by H/R.

CONCLUSION

Ad/vIL-10 significantly inhibits the upregulation of endothelial adhesion molecule expressions and the increase of adhesion of monocytes- endothelial cells induced by H/R, indicating that vIL-10 gene transfer is of farreaching significance in the therapy of cerebrovascular inflammatory diseases, and anti-adhesion treatment may reduce H/R injury.

A synergistic antitumor effect of interleukin-2 addition with CD80 immunogene therapy for peritoneal metastasis of gastric carcinoma

The co-stimulatory molecule CD80 is a ligand of CD28, which plays a key role in the induction of cell-mediated immune responses. Many tumors, including gastric cancer, decrease the expression of CD80, which results in the failure of immune recognition. We evaluated the effect of interleukin-2 addition combined with CD80 infection on the peritoneal metastasis in gastric cancer. CD80 infection combined with interleukin-2 addition significantly increased the activated cytotoxicity of mononuclear cells compared to CD80 gene infection and compared to the lacZ control group. In vivo, the survival of animals with intraperitoneal tumor was longest in those given CD80 infection with interleukin-2 addition (median survival, 46 days), followed by those given interleukin-2 (39 days), those given CD80 infection (37 days), and those given lacZ (29 days). These results suggest that interleukin-2 addition might contribute to improving the observed outcome of CD80 immunogene therapy in peritoneal metastasis of gastric carcinoma.

Cytokine gene variants and venous thrombotic risk in the BRATROS (BRAZILIAN THROMBOSIS STUDY)

INTRODUCTION

Venous thrombosis (VT) and inflammation are two closely related entities. In the present investigation we assessed whether there is a relation between genetic modifiers of the inflammatory response and the risk of VT.

MATERIALS AND METHODS

420 consecutive and unrelated patients with an objective diagnosis of deep VT and 420 matched controls were investigated. The frequencies of the following gene polymorphisms were determined in all subjects: TNF-alpha-308 G/A, LT-alpha+252 A/G, IL-6-174 G/C, IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G.

RESULTS

Overall odds ratio (OR) for VT related to TNF-alpha-308 G/A, LT-alpha+252 A/G, IL-6-174 G/C, A1 allele (4 bp repeat) of the IL1-ra 86 bp VNTR, IL-10-1082 A/G and CD-31 125 C/G were respectively: 1.0 (CI95: 0.8-1.5), 1.3 (CI95: 1.0-1.7), 1.1 (CI95: 0.9-1.5), 1.6 (CI95: 1-2.5), 1.2 (CI95: 0.8-1.7) and 0.8 (CI95: 0.6-1.1). A possible interaction between polymorphisms was observed only for the co-inheritance of the mutant alleles of the LT-alpha+252 A/G and IL-10-1082 G/A polymorphisms (OR=2; CI95: 1.1-3.8). The risk of VT conferred by factor V Leiden and FII G20210A was not substantially altered by co-inheritance with any of the cytokine gene polymorphisms.

CONCLUSIONS

Cytokine gene polymorphisms here investigated did not significantly influence venous thrombotic risk.

Treatment with an oral small molecule inhibitor of P selectin (PSI-697) decreases vein wall injury in a rat stenosis model of venous thrombosis

BACKGROUND

Vein wall injury after thrombosis is multifactorial but seems dependent on thrombus and local thrombotic and inflammatory mechanisms. We hypothesized that inhibition of vein wall injury through reduction of thrombotic and inflammatory events with P-selectin inhibition and/or low-molecular-weight heparin (LMWH) occurs independently of thrombus resolution in a rat model of venous thrombosis.

METHODS

Male rats underwent inferior vena cava (IVC) stenosis (94.4% +/- 0.5% reduction in IVC diameter) to induce thrombosis. Rats were treated from 2 days after thrombosis until they were killed 7 days later. Groups consisted of (1) PSI-697, a P-selectin inhibitor (30 mg/kg; oral gavage daily); (2) LMWH-Lovenox (LOV; enoxaparin) 3 mg/kg subcutaneously daily; (3) PSI-697 (30 mg/kg; oral gavage daily) plus LOV 3 mg/kg subcutaneously daily (PSI + LOV); (4) and untreated controls. Evaluations included thrombus mass, vein wall tensiometry (stiffness [inverse of compliance]), intimal thickness scoring by light microscopy, vein wall inflammatory mediators by enzyme-linked immunosorbent assay, and vein wall inflammatory cells by histologic evaluation.

RESULTS

Thrombus mass was not reduced by any treatment. Animals treated with PSI-697 alone, LOV alone, or PSI + LOV demonstrated significant decreases in vein wall stiffness when compared with controls. The vein wall stiffness of the PSI-697-treated groups was also significantly lower than in the LOV-only group. Animals treated with PSI-697 showed a significantly decreased intimal thickness score when compared with vehicle control IVCs. Vein wall intimal thickening was also significantly decreased in animals treated with PSI-697 vs LOV. The PSI-697 and PSI + LOV groups manifested significant decreases in the immunoregulatory and inflammatory cytokine interleukin 13 as compared with controls and LOV. Vein wall monocyte chemotactic protein 1 levels were also significantly reduced in the PSI-697 and PSI + LOV groups vs control. Only PSI-697 significantly decreased vein wall levels of platelet-derived growth factor betabeta. Both the LOV and PSI + LOV groups had significant increases in vein wall monocytes and total inflammatory cells vs controls.

CONCLUSIONS

These data suggest that both LMWH and PSI-697 inhibit vein wall injury independently of thrombus mass. P-selectin inhibition seemed superior to LMWH in measured parameters of injury and mediator inhibition.

Targeted Deletion of CCR2 Impairs Deep Vein Thombosis Resolution in a Mouse Model

CCR2 is required for monocyte recruitment in many inflammatory processes, as well as conferring Th1 lymphokine responses. Deep vein thrombosis (DVT) resolution represents a specific inflammatory response whereby the thrombus must be dissolved for restoration of blood flow. Using a stasis model of DVT in the mouse, we investigated the role of CCR2 on DVT resolution. Genetic deletion of CCR2 (CCR2-/-) was associated with larger thrombi at early and later time points, increased thrombus collagen, fewer thrombus monocytes (F4/80), and significantly impaired neovascularization. IL-2 and IFN-gamma were significantly reduced in early CCR2-/- thrombi, whereas MCP-1 was significantly increased, and Th2 lymphokines were unaffected. Supplementation of CCR2-/- mice with IFN-gamma normalized early thrombus resolution without increasing monocyte influx. Neither Ab depletion of IFN-gamma nor genetic deletion of IFN-gamma impaired early DVT resolution. Early fibrinolysis was not impaired in CCR2-/- mice, but a significant reduction in both matrix metalloproteinase (MMP)-2 and MMP-9 activity was observed. However, only MMP-9 activity was restored with administration of IFN-gamma. We conclude that an early CCR2-dependent Th1 lymphokine response predominates in normal DVT resolution, mediates this in part by MMP-9 activation, but is not solely dependent on IFN-gamma.

A role for interleukin-10 in the assessment of venous thromboembolism risk in injured patients

BACKGROUND

Management of patients with multiple trauma requires prophylaxis for venous thromboembolism (VTE). This involves recognition of the physiologic factors that are associated with VTE risk. Currently, there is no effective strategy for risk assessment. The purpose of this study is to investigate the relationship of serum P-selectin and interleuken-10 (IL-10) with VTE as a possible physiologic marker.

METHODS

Patients admitted to two trauma centers with an Injury Severity Score >/=9 had blood samples drawn and underwent duplex ultrasound scanning of the lower extremities before initiating prophylaxis at admission, on days 3 and 7, and weekly until discharge. Patients were prophylaxed according to institutional protocols.

RESULTS

One hundred eighty-six patients were enrolled with a VTE incidence of 17.8%. The population was predominantly male (60%), with a mean age of 48 years. sP-selectin levels were not statistically different between the groups (64.4 versus 74.8 pg/mL). However, IL-10 was significantly lower in the VTE group at both the initial and subsequent blood draws (21 versus 165 ng/mL, p = 0.012). Further, the ratio of sP-selectin to IL-10 (3.92 versus 0.92, p = 0.014) was statistically higher in the VTE group at admission.

CONCLUSION

An elevated sP-selectin to IL-10 ratio appears to be associated with the development of VTE in patients at high risk and may prove to be a useful clinical marker for this dreaded complication among trauma patients. Early recognition of this high-risk group improves the accuracy of the risk/benefit determination for prophylaxis and identifies a group in whom routine ultrasound screening would be cost-effective.

The role of inflammation in early and late venous thrombosis: Are there clinical implications?

Venous thrombosis is associated with a significant inflammatory response. Inflammatory cells, adhesion molecules (especially selectins), cytokines, and procoagulant microparticles appear to be associated with the thrombogenic process. Once thrombus forms, inflammatory cells are important to thrombus resolution along with fibrinolytic agents and proinflammatory mediators. Collagen and elastin breakdown by the DVT renders the vein wall stiff and non-compliant. Rapid and complete thrombus resolution should lessen vein wall damage and lessen or prevent the development of chronic venous insufficiency. Understanding the basic biology of thrombogenesis and thrombus resolution is important, as novel therapies to both prevent and treat venous thrombosis and hasten thrombus resolution should result from a better understanding of the basic biological mechanisms.

Up regulation of ICAM-1 gene expression inhibits tumour growth and liver metastasis in colorectal carcinoma

We have previously reported that decreased intercellular adhesion molecule-1 (ICAM-1) expression in cancer cells is associated with liver metastasis of colorectal cancer. In this study, we have investigated the effect of ICAM-1 gene transfection into the human colorectal cancer cell line LM-H3 on cell adhesiveness and cytotoxicity of peripheral blood mononuclear cells (PBMC) to cancer cells. Furthermore, we have investigated the effects of this gene transfer on subcutaneous tumour and liver metastases of LM-H3 in nude mice. More PBMC adhered to ICAM-1 transfected LM-H3 cells, LM-H3/ICAM-1, than to non-transfected LM-H3 cells and control LM-H3/Vector. Lysis of LM-H3/ICAM-1 cells by PBMC was significantly increased compared with LM-H3/Vector. Liver metastases with LM-H3/ICAM-1 cells were fewer in number and smaller than metastases with LM-H3/Vector. Intra-tumoural injection of ICAM-1 adenoviral vector significantly inhibited the growth of subcutaneous LM-H3 tumour. In conclusion ICAM-1 gene transfection using adenovirus vector might be an effective therapy for liver metastasis of colorectal carcinoma.

Vein wall remodeling after deep vein thrombosis involves matrix metalloproteinases and late fibrosis in a mouse model

HYPOTHESIS

Deep venous thrombosis (DVT) confers vein wall injury associated with fibrosis and extracellular matrix (ECM) turnover, likely mediated by matrix proteases. This study investigated the expression of proteases and collagen involved in early vein wall remodeling.

METHODS

In the mouse, DVT was produced by ligation of the infrarenal inferior vena cava (IVC) or sham operation, and tissue was harvested at 4, 8, and 12 days. The vein wall tissue was processed for real-time reverse transcriptase-polymerase chain reaction (6 to 8 per time point), Western immunoblotting (5 per time point), and gelatin zymography (5 per time point). Analysis of variance was used for multiple comparisons, and a P < .05 was significant.

RESULTS

Thrombus resolution was documented by a 38% decrease in the thrombosed IVC weight from day 4 to day 12 (P = .007). Total vein wall collagen increased over time, with a corresponding increase in procollagen I and III, and expression peaked at 12 days (24-fold and 6.1-fold, respectively, P < .02). Matrix metalloproteinase-2 (MMP-2) gene expression was 23-fold greater at 12 days after thrombus formation compared with sham or 4 days after thrombosis (P < .05). Total MMP-2 activity was also significantly elevated at 12 days compared with sham (P < .05). MMP-9 expression was 19-fold and 27-fold higher at days 4 and 8, respectively, relative to sham (P < .05), with no difference in activity. MMP-14 expression was twofold to 3.6-fold greater at day 12 compared with earlier time points and shams (P < .001), but no differences in protein levels were found. Urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) protein levels were not significantly different from sham over time; however, the ratio of uPA to PAI-1 was decreased through 8 days.

CONCLUSIONS

Vein wall remodeling after DVT is similar to wound healing and is associated with increased procollagen gene expression and total collagen. It is also associated with increased early MMP-9 expression, followed by MMP-2 expression and activity after DVT resolution.

CLINICAL RELEVANCE

Deep vein thrombosis is an often neglected problem that long term is associated with the postphlebitic syndrome of limb swelling, pain, and often ulceration. The basic mechanisms of the vein wall damage that results have not been delineated. The following study describes the vein wall matrix metalloproteinase gene and activity response induced over time in the vein wall after DVT. Additionally, the corresponding collagen upregulation and proximate plasmin system mediators are determined. With this knowledge, potential therapies to reduce vein wall injury directly might be possible.

Thematic review series: The immune system and atherogenesis. Cytokines affecting endothelial and smooth muscle cells in vascular disease

The cellular and extracellular matrix accumulations that comprise the lesions of atherosclerosis are driven by local release of cytokines at sites of predilection for lesion formation, and by the specific attraction and activation of cells expressing receptors for these cytokines. Although cytokines were originally characterized for their potent effects on immune and inflammatory cells, they also promote endothelial cell dysfunction and alter smooth muscle cell (SMC) phenotype and function, which can contribute to or retard vascular pathologies. This review summarizes in vivo studies that have characterized endothelial- and smooth muscle-specific effects of altering cytokine signaling in vascular disease. Although multiple reports have identified cytokines as pivotal players in endothelial and SMC responses in vascular disease, they also have highlighted the need to delineate the critical genes and specific cellular functions regulated by individual cytokine signaling pathways.

PDE4 inhibitors as new anti-inflammatory drugs: effects on cell trafficking and cell adhesion molecules expression

Phosphodiesterase 4 (PDE4) is a major cyclic AMP-hydrolyzing enzyme in inflammatory and immunomodulatory cells. The wide range of inflammatory mechanisms under control by PDE4 points to this isoenzyme as an attractive target for new anti-inflammatory drugs. Selective inhibitors of PDE4 have demonstrated a broad spectrum of anti-inflammatory activities including the inhibition of cellular trafficking and microvascular leakage, cytokine and chemokine release from inflammatory cells, reactive oxygen species production, and cell adhesion molecule expression in a variety of in vitro and in vivo experimental models. The initially detected side effects, mainly nausea and emesis, appear at least partially overcome by the 'second generation' PDE4 inhibitors, some of which like roflumilast and cilomilast are in the later stages of clinical development for treatment of chronic obstructive pulmonary disease. These new drugs may also offer opportunities for treatment of other inflammatory diseases.

Secreted Immunomodulatory Viral Proteins as Novel Biotherapeutics

Many viruses have learned to evade or subvert the host antiviral immune responses by encoding and expressing immunomodulatory proteins that protect the virus from attack by elements of the innate and acquired immune systems. Some of these viral anti-immune regulators are expressed as secreted proteins that engage specific host immune targets in the extracellular environment, where they exhibit potent anti-immune properties. We review here viral immunomodulatory proteins that have been tested as anti-inflammatory reagents in animal models of disease caused by excessive inflammation or hyperactivated immune pathways. The potential for such viral molecules for the development of novel drugs to treat immune-based or inflammatory disorders is discussed.

Deep vein thrombosis resolution is modulated by monocyte CXCR2-mediated activity in a mouse model

OBJECTIVE

To determine the role of CXCR2, the receptor for cysteine-X-cysteine (CXC) chemokines, and its primary effector cell, the neutrophil (PMN), on deep venous thrombosis (DVT) resolution.

METHODS AND RESULTS

DVT in BALB/c, anti-CXCR2 antibody-treated, and BALB/c CXCR2(-/-) mice were created by infrarenal inferior vena cava (IVC) ligation and the thrombus harvested at various time points over 21 days. The CXCR2(-/-) mice had significantly larger thrombi at early time points (days 2 to 8), and significantly decreased intrathrombus PMNs, monocytes, and neovascularization as compared with controls. Thrombus KC/CXCL1 was significantly higher at 2 days in CXCR2-/- thrombi as measured by enzyme-linked immunosorbent assay. Fibrin content was significantly higher, with less uPA gene expression at 4 days in CXCR2-/- thrombi. Late fibrotic maturation of the thrombus was delayed in the CXCR2-/- mice, with significantly decreased 8 day MMP-2 activity, whereas MMP-9 activity was elevated as compared with controls. Similar impairment in DVT resolution was found at 8 days with anti-CXCR2 inhibition. However, systemic neutropenia, unlike CXCR2 deletion, did not increase the thrombus size as compared with controls.

CONCLUSIONS

Normal DVT resolution involves CXCR2-mediated neovascularization, collagen turnover, and fibrinolysis, and it is probably primarily monocyte-dependent.

Suppression of allogeneic response by viral IL-10 gene transfer

Th1 cell activation and cytokine production shift the balance between Th1 and Th2, favoring the upregulation of proinflammatory activity that leads to destruction of allogeneic hepatocytes following transplantation. Th2-type cytokines. such as IL-10, have immune regulatory function. The aim of this study was to determine the antirejection efficacy of allogeneic hepatocytes with spheroidal shape (spheroids) genetically modified with viral IL-10 (vIL-10). Allogeneic hepatocyte spheroids, transferred vIL-10 gene by using adenovirus as the vector, were transplanted into the spleen of Nagase's analbuminemic rats (NAR). NAR transplanted with vIL-10-transfected hepatocytes showed an abrupt rise in serum albumin levels that peaked on day 7 and remained at high levels up to day 21 after transplantation. The peak level of albumin on day 7 in vIL-10-transfected NAR was eminently higher than that in nontransfected NAR. Histopathological analysis revealed that in nontransfected NAR hepatocyte spheroids were more or less rejected on day 4, and, in contrast, vIL-10-transfected spheroids were still not rejected on day 14. This protective effect correlated with sustained high vIL-10 level in the splenic vein in NAR transplanted with vIL-10-transfected hepatocyte spheroids, suggesting that vIL-10 secreted from the transplanted hepatocytes induced an active suppression of allogeneic response. This study provides evidence to support the possibility of using vIL-10 gene therapy to prevent allogeneic response in hepatocyte transplantation.

Neutropenia impairs venous thrombosis resolution in the rat

OBJECTIVES

Neutrophil influx is one of the first events in a formed deep venous thrombosis (DVT), but whether these cells are active participants in the resolution process is not clear. This study tests the hypothesis that neutrophils (PMN) are active participants in DVT resolution.

METHODS

Thrombosis was induced by inferior vena caval (IVC) ligation in male Sprague-Dawley rats, and rats were sacrificed at 2, 4, or 7 days for evaluation of the thrombus. Neutropenia was induced by rabbit anti-rat PMN serum, and controls received rabbit serum. Venography was performed at the 7-day time point. Immunohistochemical staining was performed to quantify intrathrombus PMNs and monocytes, and the myeloperoxidase (MPO) assay was performed to assess intrathrombus neutrophil activity. Intrathrombus concentrations of kerotinocyte cytokine (KC), macrophage inflammatory protein-2 (MIP-2), gamma interferon inducible protein-10 (IP-10), macrophage inflammatory protein-1 alpha (MIP-1 alpha), monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor (TNF)-alpha were quantified by enzyme immunoassay at each time point and normalized to total protein. Total collagen was determined at day 7.

RESULTS

Peripheral blood smears showed a 94% PMN reduction at 2 days (P <.05), recovering to 44% of control at 7 days. Intrathrombus PMNs were significantly lower in neutropenic rats at 2 and 4 days, but there were no differences in intrathrombus monocytes. The MPO assay confirmed reduced neutrophil activity at 4 days. Thrombi from neutropenic rats were larger at 2 and 7 days compared with controls. In vivo thrombus area at 7 days as assessed by venography was also greater in neutropenic rats as compared with controls. The intrathrombus KC concentration was increased more than 20-fold in the neutropenic rats at 2 days, but there were no significant differences in other intrathrombus chemokines. Finally, intrathrombus collagen was increased over threefold in neutropenic rats as compared with controls.

CONCLUSION

Neutropenia impairs DVT resolution by several measures, most likely by altering normal fibrinolytic activity and thrombus collagen turnover.

P-selectin inhibition decreases post-thrombotic vein wall fibrosis in a rat model

BACKGROUND

Post-deep vein thrombosis (DVT) venous insufficiency is a vexing problem despite effective anticoagulation, and is characterized by vein wall fibrosis. This study tested the hypothesis that P-selectin inhibition would decrease post-thrombotic vein wall fibrosis and associated profibrotic mediators.

METHODS

A rat stasis model of DVT was used to produce a 2-day-old DVT. Rats then received either intravenous saline (control), rPSGL-Ig (4 mg/kg) once, or daily subcutaneous low molecular weight heparin (LMWH) (0.5 mg/kg). Inferior vena cava wall was harvested 7 days after treatment and processed for thrombus size; leukocyte content; profibrotic mediators by enzyme-linked immunosorbent assay; collagen I and III mRNA expression by semiquantitative real-time polymerase chain reaction; and for collagen protein.

RESULTS

Thrombus mass and leukocyte counts were similar between the groups. Treatment with rPSGL-Ig and LMWH resulted in less vein wall collagen (P <.05). rPSGL-Ig treatment (and a similar trend for LMWH) was associated with decreased profibrotic mediators, including less IL-13, MCP-1, bFGH, and transforming growth factor-beta (P <.05). Collagen III gene expression, but not collagen I gene expression, was increased with LMWH treatment (P <.05).

CONCLUSIONS

P-selectin inhibition with rPSGL-Ig or LMWH decreases post-DVT vein wall fibrosis, and is associated with decreased vein wall profibrotic mediators. This effect is independent of thrombus mass and vein wall leukocytes.

Cellular IL-10 is more effective than viral IL-10 in decreasing venous thrombosis

BACKGROUND

Systemic administration of cellular interleukin-10 (cIL-10) and gene transfection of viral interleukin-10 (vIL-10) at thrombus induction decreases vein wall inflammation. Only cIL-10, despite sharing an 84% amino acid sequence homology with vIL-10, decreases thrombosis through mechanisms yet to be determined.

METHODS

C57BL/6 mice (Mus musculus, n99) were studied. Inferior vena caval thrombosis was created by inferior vena caval ligation and the animals were sacrificed and evaluated at days 2 and 6 after ligation. At thrombus induction groups received intravenous 0.25 microg of cIL-10, 0.25 microg of vIL-10, or saline (untreated controls). Evaluations included thrombus mass and vein wall leukocyte counts, protein levels, and reverse-transcription polymerase chain reaction mRNA levels of P- and E-selectin, monocyte chemotactic protein-1, and IL-10. Groups were compared by analysis of variance and t tests.

RESULTS

Less thrombus was noted at both days 2 and 6 in animals treated with cIL-10. At day 2 only, vein wall leukocyte counts revealed a significant decrease in neutrophils in cIL-10 animals versus controls, with no significant differences for vIL-10 animals. In cIL-10-treated animals, P-selectin protein levels were decreased at day 6, along with a decreased thrombus mass, without significant differences in E-selectin, monocyte chemotactic protein-1, or IL-10 protein levels. vIL-10 treated animals showed increased E-selectin mRNA and thrombus mass versus controls on day 6.

CONCLUSIONS

cIL-10 is more antithrombotic/anti-inflammatory than vIL-10. This may be the result of cIL-10 decreasing P-selectin protein expression and vIL-10 increasing E-selectin mRNA levels.

Interleukins in atherosclerosis: molecular pathways and therapeutic potential

Interleukins are considered to be key players in the chronic vascular inflammatory response that is typical of atherosclerosis. Thus, the expression of proinflammatory interleukins and their receptors has been demonstrated in atheromatous tissue, and the serum levels of several of these cytokines have been found to be positively correlated with (coronary) arterial disease and its sequelae. In vitro studies have confirmed the involvement of various interleukins in pro-atherogenic processes, such as the up-regulation of adhesion molecules on endothelial cells, the activation of macrophages, and smooth muscle cell proliferation. Furthermore, studies in mice deficient or transgenic for specific interleukins have demonstrated that, whereas some interleukins are indeed intrinsically pro-atherogenic, others may have anti-atherogenic qualities. As the roles of individual interleukins in atherosclerosis are being uncovered, novel anti-atherogenic therapies, aimed at the modulation of interleukin function, are being explored. Several approaches have produced promising results in this respect, including the transfer of anti-inflammatory interleukins and the administration of decoys and antibodies directed against proinflammatory interleukins. The chronic nature of the disease and the generally pleiotropic effects of interleukins, however, will demand high specificity of action and/or effective targeting to prevent the emergence of adverse side effects with such treatments. This may prove to be the real challenge for the development of interleukin-based anti-atherosclerotic therapies, once the mediators and their targets have been delineated.

Viral mimicry of cytokines, chemokines and their receptors

Viruses have evolved elegant mechanisms to evade detection and destruction by the host immune system. One of the evasion strategies that have been adopted by large DNA viruses is to encode homologues of cytokines, chemokines and their receptors--molecules that have a crucial role in control of the immune response. Viruses have captured host genes or evolved genes to target specific immune pathways, and so viral genomes can be regarded as repositories of important information about immune processes, offering us a viral view of the host immune system. The study of viral immunomodulatory proteins might help us to uncover new human genes that control immunity, and their characterization will increase our understanding of not only viral pathogenesis, but also normal immune mechanisms. Moreover, viral proteins indicate strategies of immune modulation that might have therapeutic potential.

Decrease in fibrin content of venous thrombi in selectin-deficient mice

The purpose of this study was to quantify the fibrin content of thrombi produced in a mouse model of venous thrombosis and correlate this to thrombus mass. The role of P-selectin, E-selectin, and IL-10 on thrombus fibrin content was analyzed using knockout (KO) mice. Five groups of mice were evaluated: control (N = 10), P-selectin KO (N = 7), E-selectin KO (N = 5), combined E-/P-selectin KO (N = 12), and IL-10 KO (N = 10). Venous thrombosis was induced by ligation of the infrarenal IVC. Mice were sacrificed on postoperative days (POD) 2 and 6. Thrombus mass was calculated. Sections of IVC were stained with an antibody that cross reacts with mouse fibrin. The distribution of RGB color pixels was generated from digitized micrographs of the thrombus of each animal. The mean pixel value for each group was compiled and analyzed using 2-way ANOVA. Mean pixel value per group was correlated with the mean thrombus mass per group. Color analysis demonstrated significant decreases in the analyzed fibrin content on POD-2 between the control vs E-/P-selectin KO (P < 0.05) and control vs IL-10 KO (P < 0.05) groups. In addition, significantly less fibrin staining was noted on POD-6 between the control vs E-selectin KO (P = 0.03), control vs P-selectin KO (P = 0.01), and control vs E-/P-selectin KO (P < 0.01). There was a strong overall correlation between the mean pixel value for each group and the thrombus mass (R = 0.964; P < 0.01). This study demonstrates a difference in fibrin content of thrombi produced in animals deficient in E-selectin, P-selectin, and IL-10, supporting their importance in thrombus amplification, fibrin formation, and the mass of thrombus formed.

Selectins influence thrombosis in a mouse model of experimental deep venous thrombosis

BACKGROUND

This study characterizes venous thrombosis in the mouse and examines the important role that the adhesion molecules P-selectin and E-selectin and the anti-inflammatory cytokine interleukin-10 (IL-10) play in the thrombotic process.

MATERIALS AND METHODS

C57BL/6 (wild-type) mice in a natural history protocol (Phase I) and gene-targeted (KO) mice for P-selectin, E-selectin, P/E-selectin, and IL-10 in a follow-up protocol (Phase II) were studied. Inferior vena caval thrombosis was produced by ligation just below the renal veins, and mice were sacrificed and evaluated at various time points up to 12 days later.

RESULTS

Phase I: A significant increase in neutrophils on day 2 and in monocytes on day 6 postthrombosis was found in ligated vs sham animals. An associated significant increase in vein wall P-selectin mRNA (6 h, day 2) and an increase in protein (6 h through day 6) were found, while E-selectin mRNA was significantly increased (day 2 through day 6), with a smaller increase in E-selectin protein. IL-10 mRNA increased significantly later (day 2 through day 9), with the values increasing progressively. A positive correlation existed (r = 0.77) between neutrophils and thrombosis at day 2.

PHASE II

The E-selectin and P/E-selectin double-KO mice showed the least thrombus at day 2 vs wild-type clotted mice, P < 0.01. Additionally, P/E-KO mice demonstrated the lowest inflammatory cell extravasation into the vein wall at day 2.

CONCLUSIONS

This study demonstrates an acute to chronic inflammatory response in the vein wall associated with venous thrombosis. Inhibition of selectins decreased thrombus formation.

Recipient intramuscular cotransfection of naked plasmid transforming growth factor beta1 and interleukin 10 ameliorates lung graft ischemia-reperfusion injury

OBJECTIVE

Multiple gene transfer might permit modulation of concurrent biochemical pathways involved in lung graft ischemia-reperfusion injury. In this study we analyzed whether recipient intramuscular naked plasmid cotransfection of transforming growth factor beta(1) and interleukin 10 would result in amelioration of lung graft ischemia-reperfusion injury.

METHODS

Forty-eight hours before transplantation, 6 groups (n = 6) of F344 rats received intramuscular injection of naked plasmid encoding chloramphenicol acetyltransferase, chloramphenicol acetyltransferase plus beta-galactosidase, transforming growth factor beta(1), interleukin 10, or transforming growth factor beta(1) plus interleukin 10 or were not treated. Donor lungs were flushed and stored for 18 hours at 4 degrees C before transplantation. Twenty-four hours later, grafts were assessed immediately before the animals were killed. Arterial oxygenation, wet/dry ratio, myeloperoxidase, and proinflammatory cytokines (interleukin 1, tumor necrosis factor alpha, interferon gamma, and interleukin 2) were measured, and immunohistochemistry was performed.

RESULTS

For lung graft function, the arterial oxygenation was considerably higher in the cotransfected group receiving transforming growth factor beta(1) plus interleukin 10 compared with that in all other groups (P < or =.03). The wet/dry ratio, reflecting lung edema, was reduced in the cotransfected group compared with that in control animals (nontreated, P <.02; chloramphenicol acetyltransferase, P <.03; chloramphenicol acetyltransferase plus beta-galactosidase, P <.01). Myeloperoxidase, which measures neutrophil sequestration, was also reduced with cotransfection compared with that seen in control animals (P < or =.03). All proinflammatory cytokines were decreased in the cotransfected group compared with those in all other groups (interleukin 1beta, P <.04; tumor necrosis factor alpha, P <.002; interferon gamma, P <.0001; interleukin 2, P <.03). These results indicate that cotransfection provides a synergistic benefit in graft function versus either cytokine alone, neutrophil sequestration, or inflammatory cytokine expression. Immunohistochemistry showed positive staining of transforming growth factor beta(1) plus interleukin 10 in type I and II pneumocytes and localized edema fluid.

CONCLUSIONS

Recipient intramuscular naked plasmid cotransfection of transforming growth factor beta(1) and interleukin 10 provides a synergistic effect in ameliorating lung reperfusion injury after prolonged ischemia.

Suppression of autoimmune diabetes by viral IL-10 gene transfer

Th1 cell activation and cytokine production shift the balance between Th1 and Th2, favoring the up-regulation of proinflammatory activity that leads to destruction of insulin-producing pancreatic beta cells in type 1 diabetes. Th2-type cytokines, such as IL-10, have immune regulatory function. Administration of IL-10, or IL-10 gene transfer, prevents autoimmune diabetes in nonobese diabetic (NOD) mice. However, constant administration of purified rIL-10 is not practical for long-term therapy to prevent diabetes. In this study, we transferred the BCRF-1 gene, an open reading frame in the Epstein-Barr viral genome with remarkable homology to mouse IL-10 (viral IL-10 or vIL-10), by an adeno-associated viral (AAV) vector to NOD mice to attain sustained vIL-10 gene expression. Like endogenous mouse IL-10, vIL-10 has potent immunoregulatory and immunosuppressive functions, but can be specifically distinguished from endogenous mouse IL-10 for monitoring of the transgene expression. A single systemic administration of AAV vIL-10 significantly reduced insulitis and prevented diabetes development in NOD mice. This protective effect correlated with sustained transgene expression and protein production. Moreover, splenocytes from the treated mice blocked diabetes transfer to NOD recipients, suggesting that vIL-10 induces an active suppression of autoimmunity. This study provides evidence to support the possibility of using vIL-10 gene therapy to prevent type 1 diabetes.

Interleukin-10 protects nitric oxide-dependent relaxation during diabetes: role of superoxide

Interleukin (IL)-10, an anti-inflammatory cytokine, preserves endothelial function during acute inflammation. We tested the hypotheses that IL-10 plays a protective role in blood vessels during diabetes by suppressing impairment of endothelium-dependent relaxation and that protection by IL-10 is mediated by effects on superoxide (O(2-)). Streptozotocin (150 mg/kg i.p.) or citrate buffer was injected into IL-10-deficient (IL-10(-/-)) mice and wild-type controls (IL-10(+/+)). In IL-10(+/+) and IL-10(-/-) mice, blood glucose levels were approximately 120 mg/dl after citrate administration and approximately 400 mg/dl after streptozotocin administration. Vasorelaxation was examined in arteries in vitro 12-16 weeks later. Maximum relaxation to acetylcholine (30 micromol/l) was 88 +/- 3% (means +/- SE) in nondiabetic mice and 84 +/- 3% in diabetic IL-10(+ /+) mice (P > 0.05). Thus, at this time point, diabetes did not impair endothelium-dependent relaxation in vessels in wild-type mice. In contrast, maximum relaxation in vessels from diabetic IL-10(-/-) mice was significantly decreased (74 +/- 5%) compared with nondiabetic IL-10(-/-) mice (93 +/- 2%, P < 0.05). Superoxide dismutase with polyethylene glycol (PEG-SOD) restored impaired responses to acetylcholine to levels seen in controls. Responses to acetylcholine also were improved by allopurinol (an inhibitor of xanthine oxidase) in vessels from diabetic IL-10(- /-) mice. Thus, diabetes produces greater impairment of relaxation to acetylcholine in IL-10(-/-) mice than in IL-10(+/ +) mice. These findings provide direct evidence that IL-10 impedes mechanisms of endothelial dysfunction during diabetes. Restoration of vasorelaxation with PEG-SOD or allopurinol suggests that the mechanism(s) by which IL-10 preserves endothelium-dependent vasorelaxation involves O(2-), perhaps by reducing production of O(2-) by xanthine oxidase.

Viral interleukin-10 gene inhibition of inflammation, osteoclastogenesis, and bone resorption in response to titanium particles

OBJECTIVE

To evaluate the potential of viral interleukin-10 (vIL-10) gene therapy as an approach to prevent wear debris-induced inflammation, osteoclastogenesis, and bone resorption as it relates to periprosthetic osteolysis in patients with total joint replacements.

METHODS

Replication-defective adenovirus vectors expressing vIL-10 (AdvIL-10) or LacZ (AdLacZ) target genes were used to transduce fibroblast-like synoviocytes (FLS) in vitro, and the effects of these cells on wear debris-induced proinflammatory cytokine production and receptor activator of nuclear factor kappaB ligand + macrophage colony-stimulating factor splenocyte osteoclastogenesis were assessed by enzyme-linked immunosorbent assay and tartrate-resistant acid phosphatase assay. The effects of AdvIL-10 administration on wear debris-induced osteolysis in vivo were analyzed using the mouse calvaria model, in which AdLacZ was used as the control.

RESULTS

In the presence of AdLacZ-infected FLS, titanium particle-stimulated macrophages exhibited a marked increase in secretion of tumor necrosis factor alpha (TNFalpha) (6.5-fold), IL-6 (13-fold), and IL-1 (5-fold). Coculture with AdvIL-10-transduced FLS suppressed cytokine secretion to basal levels, while addition of an anti-IL-10 neutralizing antibody completely blocked this effect. The vIL-10-transduced FLS also inhibited osteoclastogenesis 10-fold in an anti-IL-10-sensitive manner. In vivo, titanium implantation resulted in a 2-fold increase in osteoclasts (P < 0.05) and in a 2-fold increase in sagittal suture area (P < 0.05). This increase over control levels was completely blocked in mice receiving intraperitoneal injections of AdvIL-10, all of whom had measurable serum vIL-10 levels for the duration of the experiment. Immunohistochemistry demonstrated reduced cyclooxygenase 2 and TNFalpha expression in AdvIL-10-infected animals.

CONCLUSION

This study demonstrates that gene delivery of vIL-10 inhibits 3 processes critically involved in periprosthetic osteolysis: 1) wear debris-induced proinflammatory cytokine production, 2) osteoclastogenesis, and 3) osteolysis.

Interleukin-8 administration enhances venous thrombosis resolution in a rat model

BACKGROUND

Therapy for deep vein thrombosis (DVT) resolution in those patients in whom a complication or contraindication to anticoagulation occurs is limited. As prior work suggests that thrombus maturation involves early influx of neutrophils (PMN) and neovascularization, we hypothesized that administering the proinflammatory/proangiogenic chemokine interleukin (IL)-8 might accelerate thrombus resolution.

MATERIALS AND METHODS

An established rodent model of DVT (inferior vena cava [IVC] ligation) was used whereby daily intravenous recombinant human IL-8 (1 microg) or vehicle control was administered, with sacrifice at 4 and 8 days. Prior to sacrifice and at harvest, duplex ultrasound of the DVT and femoral venous pressure measurements were performed. Thrombi were analyzed by immunohistochemical techniques for PMN, monocytes, and neovascularization; for chemokines, by enzyme-linked immunoassay; and fibrosis, by hydroxyproline assay and trichrome staining.

RESULTS

IL-8 accelerated thrombus dissolution 4 days after IVC ligation, with 6-fold increased thrombus blood flow by duplex ultrasound and a 23% increased absolute femoral venous pressure compared with controls (both P < 0.05). These findings may be partially explained by the fact that animals receiving IL-8, as compared with controls, had 2.5-fold greater thrombus neovascularization (with a trend continuing to 8 days) and increased PMN at 4 days. Thrombus vascular endothelial growth factor was significantly reduced at 8 days postligation, while monocyte chemotactic protein-1 and macrophage inflammatory protein-1alpha were not altered by IL-8 administration. At 8 days post-IVC-ligation, fibrosis was 12-fold greater with IL-8 treatment compared with controls.

CONCLUSIONS

A proinflammatory/proangiogenic thrombus milieu, as conferred by IL-8, enhances thrombus resolution and underscores the important relationship between neovascularity and inflammation.

Ex vivo adenovirus mediated gene transfection of human conjunctival epithelium

AIM

To investigate the efficacy of "ex vivo" adenoviral vector mediated gene transfection of human conjunctival epithelial cell as a possible route for gene therapy for the distribution of anti-inflammatory agents for the potential treatment of immune mediated ocular inflammatory disorders.

METHODS

Human conjunctival cells (HCs) were cultured with various concentrations of recombinant adenoviral vectors carrying a reporter gene LacZ, GFP, or an immunomodulating cytokine vIL-10. vIL-10 in culture supernatant was detected by sandwich ELISA and biological activity was assessed by suppression of ConA stimulated splenocyte proliferation. X-gal and GFP expression was assessed by histochemistry.

RESULTS

The extent of adenoviral vector mediated transfer of both reporter genes and vIL-10 was dose dependent. LacZ expression could be detected for at least 50 day after infection with multiple of infection (MOI) 200. Following AdCMVvIL-10 transduction, vIL-10 protein expression occurred between 4-6 days post-transduction, and was maintained at a detectable level for at least 1 month. Secreted vIL-10 showed biological activity, significantly inhibiting Con A induced splenocyte proliferation. Additionally, transfection of HCs with two Adv vectors, one carrying LacZ and the other carrying GFP, resulted in co-expression within a single cell.

CONCLUSION

These results confirm previous successful adenoviral vector mediated gene transfer to HCs and further show that expression can be maintained. Furthermore the data show HCs can secrete biologically active vIL-10 that could be developed as a strategy to suppress immune mediated disorders. The successful co-transduction of HCs as described for other tissues, opens avenues to develop a multiple target gene therapy locally.

Anti-inflammatory mechanisms in the vascular wall

The role of vascular cells during inflammation is critical and is of particular importance in inflammatory diseases, including atherosclerosis, ischemia/reperfusion, and septic shock. Research in vascular biology has progressed remarkably in the last decade, resulting in a better understanding of the vascular cell responses to inflammatory stimuli. Most of the vascular inflammatory responses are mediated through the IkappaB/nuclear factor-kappaB system. Much recent work shows that vascular inflammation can be limited by anti-inflammatory counteregulatory mechanisms that maintain the integrity and homeostasis of the vascular wall. The anti-inflammatory mechanisms in the vascular wall involve anti-inflammatory external signals and intracellular mediators. The anti-inflammatory external signals include the anti-inflammatory cytokines, transforming growth factor-beta, interleukin-10 and interleukin-1 receptor antagonist, HDL, as well as some angiogenic and growth factors. Physiological laminar shear stress is of particular importance in protecting endothelial cells against inflammatory activation. Its effects are partly mediated through NO production. Finally, endogenous cytoprotective genes or nuclear receptors, such as the peroxisome proliferator-activated receptors, can be expressed by vascular cells in response to proinflammatory stimuli to limit the inflammatory process and the injury.

IL-10-deficient mice demonstrate multiple organ failure and increased mortality during Escherichia coli peritonitis despite an accelerated bacterial clearance

To determine the role of endogenous IL-10 in local antibacterial host defense and in the development of a systemic inflammatory response syndrome during abdominal sepsis, IL-10 gene-deficient (IL-10(-/-)) and wild-type (IL-10(+/+)) mice received an i.p. injection with Escherichia coli. Peritonitis was associated with a bacterial dose-dependent increase in IL-10 concentrations in peritoneal fluid and plasma. The recovery of E. coli from the peritoneal fluid, blood, and lungs was diminished in IL-10(-/-) mice, indicating that endogenous IL-10 impaired bacterial clearance. Despite a lower bacterial load, IL-10(-/-) mice had higher concentrations of TNF, macrophage inflammatory protein-2 and keratinocyte in peritoneal fluid and plasma, and demonstrated more severe multiple organ damage as indicated by clinical chemistry and histopathology. Furthermore, IL-10(-/-) mice showed an increased neutrophil recruitment to the peritoneal cavity. To examine the role of elevated TNF levels in the altered host response in IL-10(-/-) mice, the effect of a neutralizing anti-TNF mAb was determined. Anti-TNF did not influence the clearance of E. coli in either IL-10(+/+) or IL-10(-/-) mice. Furthermore, anti-TNF did not affect leukocyte influx in the peritoneal fluid, multiple organ damage, or survival in IL-10(+/+) mice. In IL-10(-/-) mice, anti-TNF partially attenuated neutrophil recruitment and multiple organ damage, and prevented the increased lethality. These data suggest that although endogenous IL-10 facilitates the outgrowth and dissemination of bacteria during E. coli peritonitis, it protects mice from lethality by attenuating the development of a systemic inflammatory response syndrome by a mechanism that involves inhibition of TNF release.

Virokines: novel immunomodulatory agents

Since the discovery of virokines in the 1980s, much time and research has been dedicated to exploring their potential use as therapeutic agents. Simply put, virokines are virally encoded proteins that are secreted from the infected host cell. Most of these proteins possess the ability to modulate different aspects of the host immune system, to better maintain a suitable habitat for viral replication. These proteins are often highly homologous to host immune proteins but are often smaller and more powerful. Examples of virokines include viral secreted proteins that: block components of the complement system, act as serine protease inhibitors, function as chemokine and cytokine agonists or antagonists and contribute to cell proliferation. Many of these proteins are currently being investigated for use as novel therapeutic immunomodulators to manage immune disorders, inflammation after trauma, graft rejection and autoimmune diseases.

Host-related immunomodulators encoded by poxviruses and herpesviruses

In the past year, important advances have been made in the area of host-related immunomodulatory genes encoded by the larger DNA viruses, particularly for the poxviruses and herpesviruses. Not only has the repertoire of viral immunomodulator homologs expanded as a result of sequencing the complete genome of another six, large DNA viruses, but also new concepts of how they work have been proposed and in some cases supported by in vivo evidence. Recent developments have been made in understanding a spectrum of host-related viral modulators, including complement control proteins, TNF-receptor homologs, IL-18 binding proteins, viral interleukins (vIL-6 and vIL-10), chemokine mimics and chemokine receptor homologs.