Production of angiogenic activity by human monocytes requires an L-arginine/nitric oxide-synthase-dependent effector mechanism

The effect of L-Arginine therapy on achilles tendon healing: A histological and biomechanical investigation in an animal model

PURPOSE

Several clinical and experimental studies have revealed that L-Arginine, which has antioxidant properties, accelerates tissue healing. This study examined the in vivo effects of oral L - Arginine supplementation on tendon regeneration in Wistar rats.

METHOD

For each weighting of an average of 250-300 g, 24 Wistar rats were separated into three equal groups. Each rat's right hind leg Achilles tendons were tenotomized and then repaired. The first group (Control) was followed up with a regimen of standard food and water. In the second group (L-Arg Low Dose), 300 mg/kg, and in the third group (L-Arg High Dose), 600 mg/kg L-Arginine was administered in water daily with a regimen of standard food and water ad libitum. After eight weeks, the rats were sacrificed, and the tendons were histologically and biomechanically analyzed.

RESULTS

Tendon peak strength values of the L-Arg Low Dose and L-Arg High Dose groups were similar but significantly higher than the control group. A statistically significant difference was observed between the groups in terms of ground substance, fiber arrangement, cellularity, hyalinization, and GAG properties ( p = 0.05, p = 0.002, p = 0.016, p = 0.027, p = 0.05). There was no statistically significant difference between the groups according to the histological examination of collagen properties, fiber structure, tenocyte properties, rounding of the nuclei, and collagen stainability. (p = 0.999, p = 0.061, p = 0.195, p = 0.195, p = 0.130). No mortality, wound complications, or re-ruptures were observed.

CONCLUSION

Compared with the control group, histologically and biomechanically distinct therapeutic effects of L-Arginine supplementation on tendon healing were determined.

LEVEL OF CLINICAL EVIDENCE

5.

Nucleic acid-based therapeutics for dermal wound healing

Non-healing wounds have long been the subject of scientific and clinical investigations. Despite breakthroughs in understanding the biology of delayed wound healing, only limited advances have been made in properly treating wounds. Recently, research into nucleic acids (NAs) such as small-interfering RNA (siRNA), microRNA (miRNA), plasmid DNA (pDNA), aptamers, and antisense oligonucleotides (ASOs) has resulted in the development of a latest therapeutic strategy for wound healing. In this regard, dendrimers, scaffolds, lipid nanoparticles, polymeric nanoparticles, hydrogels, and metal nanoparticles have all been explored as NA delivery techniques. However, the translational possibility of NA remains a substantial barrier. As a result, different NAs must be identified, and their distribution method must be optimized. This review explores the role of NA-based therapeutics in various stages of wound healing and provides an update on the most recent findings in the development of NA-based nanomedicine and biomaterials, which may offer the potential for the invention of novel therapies for this long-term condition. Further, the challenges and potential for miRNA-based techniques to be translated into clinical applications are also highlighted.

Beneficial Effects of Caffeic Acid Phenethyl Ester on Wound Healing in a Diabetic Mouse: Role of VEGF and NO

Cutaneous wound healing is delayed in patients with diabetes. Caffeic acid phenethyl ester (CAPE) has been identified as an effective constituent of propolis with improved wound healing abilities via an oxidative stress decrease. However, its impact on wound healing in diabetic models and its underlying mechanisms remain unclear. Determining the vascular endothelial growth factor (VEGF) contents in a human vascular smooth muscle cell (VSMC)-conditioned medium was assessed using human VEGF immunoassay and vascular reactivity using porcine coronary artery rings. Later, C57BL/6 or db/db mice were anesthetized, after which a 6-mm biopsy punch was manipulated for perforation via the back skin. Subsequently, CAPE was applied to the wound and changed daily. Furthermore, the injury in each mouse was digitally photographed, and the wound area was quantified. We observed that CAPE increased VEGF levels in human VSMC-conditioned medium, improved endothelium-dependent nitric oxide (NO)-mediated vasorelaxation, inhibited U46619-induced vasoconstriction porcine coronary artery, and enhanced cutaneous wound healing in the diabetic mouse model. Hence, we propose that CAPE improves wound healing in diabetic mice, which is aided by increased VEGF and NO expression.

Selective Inhibitors of the Inducible Nitric Oxide Synthase as Modulators of Cell Responses in LPS-Stimulated Human Monocytes

Inducible nitric oxide synthase (iNOS) is a crucial enzyme involved in monocyte cell response towards inflammation, and it is responsible for the production of sustained amounts of nitric oxide. This free radical molecule is involved in the defense against pathogens; nevertheless, its continuous and dysregulated production contributes to the development of several pathological conditions, including inflammatory and autoimmune diseases. In the present study, we investigated the effects of two new iNOS inhibitors, i.e., 4-(ethanimidoylamino)-N-(4-fluorophenyl)benzamide hydrobromide (FAB1020) and N-{3-[(ethanimidoylamino)methyl]benzyl}-l-prolinamidedihydrochloride (CM554), on human LPS-stimulated monocytes, using the 1400 W compound as a comparison. Our results show that CM544 and FAB1020 are selective and decrease cytotoxicity, IL-6 secretion and LPS-stimulated monocyte migration. Furthermore, the modulation of iNOS, nitrotyrosine and Nrf2 were analyzed at the protein level. Based on the collected preliminary results, the promising therapeutic value of the investigated compounds emerges, as they appear able to modulate the pro-inflammatory LPS-stimulated response in the low micromolar range in human monocytes.

Nitric Oxide and Hydrogen Sulfide Regulation of Ischemic Vascular Growth and Remodeling

Ischemic vascular remodeling occurs in response to stenosis or arterial occlusion leading to a change in blood flow and tissue perfusion. Altered blood flow elicits a cascade of molecular and cellular physiological responses leading to vascular remodeling of the macro- and micro-circulation. Although cellular mechanisms of vascular remodeling such as arteriogenesis and angiogenesis have been studied, therapeutic approaches in these areas have had limited success due to the complexity and heterogeneous constellation of molecular signaling events regulating these processes. Understanding central molecular players of vascular remodeling should lead to a deeper understanding of this response and aid in the development of novel therapeutic strategies. Hydrogen sulfide (H₂ S) and nitric oxide (NO) are gaseous signaling molecules that are critically involved in regulating fundamental biochemical and molecular responses necessary for vascular growth and remodeling. This review examines how NO and H₂ S regulate pathophysiological mechanisms of angiogenesis and arteriogenesis, along with important chemical and experimental considerations revealed thus far. The importance of NO and H₂ S bioavailability, their synthesis enzymes and cofactors, and genetic variations associated with cardiovascular risk factors suggest that they serve as pivotal regulators of vascular remodeling responses. © 2019 American Physiological Society. Compr Physiol 9:1213-1247, 2019.

S-Nitrosoglutathione loaded poly(lactic-co-glycolic acid) microparticles for prolonged nitric oxide release and enhanced healing of methicillin-resistant Staphylococcus aureus-infected wounds

Methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds have become a significant clinical issue worldwide. Recently, nitric oxide (NO) has emerged as a potent antibacterial agent against MRSA infections and a wound-healing enhancer. Nevertheless, clinical applications of NO have been largely restricted by its gaseous state and short half-life. In this study, our aim was to develop S-nitrosoglutathione (GSNO, an endogenous NO donor)-loaded poly(lactic-co-glycolic acid) [PLGA] microparticles (GSNO-MPs) that release NO over a prolonged period, to accelerate the healing of MRSA-infected wounds with less frequent dosing. GSNO was successfully encapsulated into PLGA microparticles by a solid-in-oil-in-water emulsion solvent evaporation method. Scanning electron microscopy and X-ray diffraction analyses confirmed the successful fabrication of GSNO-MPs. The latter released NO in a prolonged manner over 7 days and exerted a remarkable antibacterial activity against MRSA in a concentration- and time-dependent manner. Moreover, GSNO-MPs had good antibacterial efficacy and were found to accelerate wound healing in a mouse model of MRSA-infected wounds. Therefore, NO-releasing MPs devised in this study may be a promising option for the treatment of cutaneous wounds infected by drug-resistant bacteria such as MRSA.

Establishment of an in ovo chick embryo yolk sac membrane (YSM) assay for pilot screening of potential angiogenic and anti-angiogenic agents

Angiogenesis, the process of new blood vessel formation from pre-existing vessels, is essential for growth and development. Development of drugs that can accelerate or decelerate angiogenesis in the context of various diseases requires appropriate preclinical screening. As angiogenesis involves complex cellular and molecular processes, in vivo studies are superior to in vitro investigations. Conventional in vitro, in vivo, and ex ovo models of angiogenesis are time consuming and tedious, and require sophisticated infrastructure for embryo culture. In the present study, we established an in ovo chick embryo yolk sac membrane (YSM) assay for angiogenesis and tested the angiogenic potential of arginine, conditioned medium (CM) from human adipose tissue and placenta-derived mesenchymal stem cells (ADMSCs-CM and PDMSCs-CM), avastin and vitamin C. The obtained results were confirmed with the routinely employed chick embryo Chorioallantoic Membrane (CAM) assay. Both assays revealed the pro-angiogenic nature of arginine, ADMSCs-CM, and PDMSCs-CM, and the anti-angiogenic effect of avastin and vitamin C. This novel in ovo YSM model is simple, reproducible, and highly economic in terms of the time frame and cost incurred. The proposed model is thus a suitable substitute to the CAM model for pilot screening of potential angiogenic and anti-angiogenic agents.

A frog cathelicidin peptide effectively promotes cutaneous wound healing in mice

Although cathelicidins in mammals have been well characterized, little is known about the function of cathelicidin in amphibians. In the present study, a novel 24-residue peptide (cathelicidin-NV, ARGKKECKDDRCRLLMKRGSFSYV) belonging to the cathelicidin family was identified from the skin of the plateau frog Nanorana ventripunctata. Cathelicidin-NV showed strong wound healing-promoting activity in a murine model with a full-thickness dermal wound. It directly enhanced the proliferation of keratinocyte cells, resulting in accelerated re-epithelialization of the wound site. Cathelicidin-NV also promoted the proliferation of fibroblasts, the differentiation of fibroblasts to myofibroblasts and collagen production in fibroblasts, which are implicated in wound contraction and repair processes. Furthermore, cathelicidin-NV promoted the release of monocyte chemoattractant protein-1, tumor necrosis factor-α, vascular endothelial growth factor and transforming growth factor-β1 in vivo and in vitro, which are essential in the wound-healing processes such as migration, proliferation and differentiation. The MAPK (ERK, JNK and p38) signaling pathways were involved in the wound healing-promoting effect. Additionally, unlike other cathelicidins, cathelicidin-NV did not have any direct effect on microbes and showed no cytotoxicity and hemolytic activity toward mammalian cells at concentrations up to 200 µg/ml. This current study may facilitate the understanding of the cellular and molecular events that underlie quick wound healing in N. ventripunctata. In addition, the combination of these properties makes cathelicidin-NV an excellent candidate for skin wound therapeutics.

Application of stem cell/growth factor system, as a multimodal therapy approach in regenerative medicine to improve cell therapy yields

Stem cells hold a great promise for regenerative medicine, especially for replacing cells in infarcted organ that hardly have any intrinsic renewal capacity, including heart and brain. Signaling pathways that regulate pluripotency or lineage-specific gene and protein expression have been the major focus of stem cell research. Between them, there are some well known signaling pathways such as GF/GFR systems, SDF-1α/CXC4 ligand receptor interaction and PI3K/Akt signaling, and cytokines may regulate cell fate decisions, and can be utilized to positively influence cell therapy outcomes or accentuate synergistic compliance. For example, contributing factors in the progression of heart failure are both the loss of cardiomyocytes after myocardial infarction, and the absence of an adequate endogenous repair signaling. Combining cell engraftment with therapeutic signaling factor delivery is more exciting in terms of host progenitor/donor stem cell survival and proliferation. Thus stem cell-based therapy, besides triggering signaling pathways through GF/GFR systems can become a realistic option in regenerative processes for replacing lost cells and reconstituting the damaged organ, as before.

The role of macrophage lineage cells in kidney graft rejection and survival

Large numbers of macrophage lineage cells are present in transplants undergoing ischemia-reperfusion injury and rejection, and their presence correlates with a high probability of rejection. However, the extent to which monocytes and macrophages contribute to kidney graft rejection is poorly understood. The heterogeneity of the monocyte/macrophage lineage cells could be one of the reasons why these cells have been neglected up to now. Circulating monocytes can be divided into various subsets, which are able to give rise to tissue macrophages and dendritic cells. Macrophages are believed to be highly plastic cells that can respond to environmental signals by changing their phenotype and function. Macrophages have established roles in early and late kidney graft inflammation, tissue homeostasis, remodeling, and repair. In kidney transplantation, macrophages are believed to play a role in both damage and repair of the graft, depending on the type of macrophages involved, the environmental drive, and the time after transplantation. The heterogeneity and plasticity of monocytes and macrophages are obstacles to translating the functional relevance of this cell lineage to diagnostic and prognostic clinical parameters and to defining specific, macrophage-related, therapeutic targets. Recent evidence has indicated an immunomodulatory role for the so-called regulatory macrophages in induction of tolerance in kidney transplant recipients. In this article, we summarize current views on monocyte/macrophage immunobiology in kidney transplantation. Key issues for ongoing research are discussed.

Targeting the intragraft microenvironment and the development of chronic allograft rejection

In this review, we discuss a paradigm whereby changes in the intragraft microenvironment promote or sustain the development of chronic allograft rejection. A key feature of this model involves the microvasculature including (a) endothelial cell (EC) destruction, and (b) EC proliferation, both of which result from alloimmune leukocyte- and/or alloantibody-induced responses. These changes in the microvasculature likely create abnormal blood flow patterns and thus promote local tissue hypoxia. Another feature of the chronic rejection microenvironment involves the overexpression of vascular endothelial growth factor (VEGF). VEGF stimulates EC activation and proliferation and it has potential to sustain inflammation via direct interactions with leukocytes. In this manner, VEGF may promote ongoing tissue injury. Finally, we review how these events can be targeted therapeutically using mTOR inhibitors. EC activation and proliferation as well as VEGF-VEGFR interactions require PI-3K/Akt/mTOR intracellular signaling. Thus, agents that inhibit this signaling pathway within the graft may also target the progression of chronic rejection and thus promote long-term graft survival.

Differentiation state determines neural effects on microvascular endothelial cells

Growing evidence indicates that nerves and capillaries interact paracrinely in uninjured skin and cutaneous wounds. Although mature neurons are the predominant neural cell in the skin, neural progenitor cells have also been detected in uninjured adult skin. The aim of this study was to characterize differential paracrine effects of neural progenitor cells and mature sensory neurons on dermal microvascular endothelial cells. Our results suggest that neural progenitor cells and mature sensory neurons have unique secretory profiles and distinct effects on dermal microvascular endothelial cell proliferation, migration, and nitric oxide production. Neural progenitor cells and dorsal root ganglion neurons secrete different proteins related to angiogenesis. Specific to neural progenitor cells were dipeptidyl peptidase-4, IGFBP-2, pentraxin-3, serpin f1, TIMP-1, TIMP-4 and VEGF. In contrast, endostatin, FGF-1, MCP-1 and thrombospondin-2 were specific to dorsal root ganglion neurons. Microvascular endothelial cell proliferation was inhibited by dorsal root ganglion neurons but unaffected by neural progenitor cells. In contrast, microvascular endothelial cell migration in a scratch wound assay was inhibited by neural progenitor cells and unaffected by dorsal root ganglion neurons. In addition, nitric oxide production by microvascular endothelial cells was increased by dorsal root ganglion neurons but unaffected by neural progenitor cells.

Key Features of the Intragraft Microenvironment that Determine Long-Term Survival Following Transplantation

In this review, we discuss how changes in the intragraft microenvironment serve to promote or sustain the development of chronic allograft rejection. We propose two key elements within the microenvironment that contribute to the rejection process. The first is endothelial cell proliferation and angiogenesis that serve to create abnormal microvascular blood flow patterns as well as local tissue hypoxia, and precedes endothelial-to-mesenchymal transition. The second is the overexpression of local cytokines and growth factors that serve to sustain inflammation and, in turn, function to promote a leukocyte-induced angiogenesis reaction. Central to both events is overexpression of vascular endothelial growth factor (VEGF), which is both pro-inflammatory and pro-angiogenic, and thus drives progression of the chronic rejection microenvironment. In our discussion, we focus on how inflammation results in angiogenesis and how leukocyte-induced angiogenesis is pathological. We also discuss how VEGF is a master control factor that fosters the development of the chronic rejection microenvironment. Overall, this review provides insight into the intragraft microenvironment as an important paradigm for future direction in the field.

Capillary rarefaction, hypoxia, VEGF and angiogenesis in chronic renal disease

Tubulointerstitial hypoxia and peritubular capillary rarefaction are typical features of chronic progressive renal disease. In response to low oxygen supply, hypoxia-inducible factors (HIFs) are activated but until now, it is unclear if this increased expression leads to a stabilization of the disease process and thus is nephroprotective or contributes to interstitial fibrosis and/or tubular atrophy. This duality has also been described as far as vascular endothelial growth factor (VEGF), one of the major target genes of HIFs, is concerned. On the one hand, neoangiogenesis driven by VEGF, if intact, ameliorates hypoxia, on the other, VEGF is a potent pro-inflammatory mediator and neoangiogenesis, if defective because interference by other pathologies exaggerates injury. In summary, experimental data support the idea that dependent on timing and predominant pathology, hypoxia counter-regulatory factors exert beneficial or undesirable effects. Thus, before their therapeutic potential can be fully explored, a better way to characterize the clinical and pathophysiological situation in an individual patient is mandatory.

Global gene expression profile progression in Gaucher disease mouse models

BACKGROUND

Gaucher disease is caused by defective glucocerebrosidase activity and the consequent accumulation of glucosylceramide. The pathogenic pathways resulting from lipid laden macrophages (Gaucher cells) in visceral organs and their abnormal functions are obscure.

RESULTS

To elucidate this pathogenic pathway, developmental global gene expression analyses were conducted in distinct Gba1 point-mutated mice (V394L/V394L and D409 V/null). About 0.9 to 3% of genes had altered expression patterns (≥ ± 1.8 fold change), representing several categories, but particularly macrophage activation and immune response genes. Time course analyses (12 to 28 wk) of INFγ-regulated pro-inflammatory (13) and IL-4-regulated anti-inflammatory (11) cytokine/mediator networks showed tissue differential profiles in the lung and liver of the Gba1 mutant mice, implying that the lipid-storage macrophages were not functionally inert. The time course alterations of the INFγ and IL-4 pathways were similar, but varied in degree in these tissues and with the Gba1 mutation.

CONCLUSIONS

Biochemical and pathological analyses demonstrated direct relationships between the degree of tissue glucosylceramides and the gene expression profile alterations. These analyses implicate IFNγ-regulated pro-inflammatory and IL-4-regulated anti-inflammatory networks in differential disease progression with implications for understanding the Gaucher disease course and pathophysiology.

Increased caveolin-1 expression associated with prolonged overall survival rate in hepatocellular carcinoma

AIMS

Recent study indicates that the binding of caveolin-1 (CAV1), the essential constituent of caveolae, to endothelial nitric oxide synthase (eNOS) prevents nitric oxide (NO) production in cirrhotic human liver. However, their interplay in hepatocellular carcinoma (HCC) remains undetermined.

METHODS

Paraffin-embedded sections from 73 HCC patients were included in this study. The expression patterns of CAV1 and eNOS determined by immunohistochemistry were correlated with the clinicopathological characteristics and overall survival.

RESULTS

Although CAV1 expression did not correlate with any clinicopathological characteristic, increased CAV1 expression was associated with prolonged overall survival (p = 0.021), even when using the multivariate Cox's regression model (OR = 0.25, 95%CI = 0.08-0.72, p = 0.011). eNOS expression was correlated with an increased histological grade (p = 0.002) and intriguingly, the patients had a decreased overall survival when their lesions presented with high eNOS but low CAV1 expression concomitantly (p = 0.003). Meanwhile, the increased CAV1/eNOS merged level determined by immunofluorescence was significantly associated with a decreased histological grade and better overall survival (p = 0.023 and 0.001, respectively).

CONCLUSIONS

Our results suggest CAV1 may play a tumour-suppressive role and can serve as a predictive biomarker in HCC. The impacts of CAV1 on hepatocarcinogenesis may occur partly through its modulation of eNOS.

Topical application of dressing with amino acids improves cutaneous wound healing in aged rats

The principal goal in treating surgical and non-surgical wounds, in particular for aged skin, is the need for rapid closure of the lesion. Cutaneous wound healing processes involve four phases including an inflammatory response with the induction of pro-inflammatory cytokines. If inflammation develops in response to bacterial infection, it can create a problem for wound closure. Reduced inflammation accelerates wound closure with subsequent increased fibroblast function and collagen synthesis. On the contrary, prolonged chronic inflammation results in very limited wound healing. Using histological and immunohistochemical techniques, we investigated the effects of a new wound dressing called Vulnamin that contains four essential amino acids for collagen and elastin synthesis plus sodium ialuronate (Na-Ial), compared with Na-Ial alone, in closure of experimental cutaneous wounds of aged rats. Our results showed that the application of Vulnamin dressings modulated the inflammatory response with a reduction in the number of inflammatory cells and inducible nitric oxide synthase (iNOS) immunolocalisation, while increasing endothelial nitric oxide synthase (eNOS) and transforming growth factor-beta1 (TGF-beta1) immunolocalisation. Furthermore, the dressing increased the distribution density of fibroblasts and aided the synthesis of thin collagen fibers resulting in a reduction in healing time. The nutritive approach using this new wound dressing can provide an efficacious and safe strategy to accelerate wound healing in elderly subjects, simplifying therapeutic procedures and leading to an improved quality of life.

Significance of vascular endothelial growth factor, interleukin-18 and nitric oxide in patients with breast cancer: correlation with carbohydrate antigen 15.3

The aim of this study was to determine serum concentrations of angiogenic factors including vascular endothelial growth factor (VEGF), interleukin 18 (IL-18) and nitric oxide (NO) in patients with breast cancer and to evaluate whether these factors will be correlated with CA 15.3, as a routine tumor marker for breast cancer or not. This study was conducted on 44 patients with breast cancer and 15 healthy individuals as a control group. The results demonstrated significant increase in serum IL-18, NO and CA 15.3 levels in sera of breast cancer patients when compared to those of the control group (P < 0.001, P = 0.016 and P < 0.001, respectively). However, the mean serum level of VEGF in patients as showed insignificant increase compared to that of the controls was not significant (P = 0.311). Sensitivity of CA 15.3, VEGF, IL-18 and NO to detect patients with disease was 52.2, 21.3, 77.2 and 70.4 %, respectively. In addition, positive status of serum CA 15.3 and/or IL-18 was found in 39 out of 44 (88.6 %) patients, and the positive status of serum CA 15.3 and/or NO was only found in 35 out of 44 (79.5 %). In conclusion, the simultaneous determination of IL-18 or NO in combination with the CA 15.3 may increase the sensitivity to diagnose breast cancer and may aid in disease prognosis.

MAPKAPK-2 signaling is critical for cutaneous wound healing

Cutaneous wound healing is a complex process, which is heavily dependent on successful inflammatory action. Mitogen-activated protein kinase (MAPK)-activated protein kinase-2 (MAPKAPK-2 or MK2), a major substrate of p38 MAPK, has been shown to be a major player in multiple inflammatory diseases, but its role in cutaneous wound healing has not yet been explored. In this study, by comparing excisional wounds made on the backs of MK2 knockout (KO) and MK2 wild-type (WT) mice, we found that the kinetics of wound healing are significantly affected by the absence of MK2 (P=0.010 to P<0.001). Histological examination showed a higher level of acanthosis of the migrating wound keratinocyte layer as well as a higher level of collagen deposition in the granulation tissue of the wounds from MK2 WT mice compared with those from MK2 KO mice. Interestingly, although MK2 did not influence macrophage and neutrophil infiltration of the wounds, the expression of many cytokines and chemokines was significantly affected at different days post wounding. Furthermore, the delayed healing rate of wounds in MK2 KO mice can be significantly improved by passive transfer of macrophages with intact MK2. Overall, these results show a critical role for MK2 gene expression in macrophages participating in the process of cutaneous wound healing.

Enhanced antitumor efficacy of vasculostatin (Vstat120) expressing oncolytic HSV-1

Oncolytic viral (OV) therapy is a promising therapeutic modality for brain tumors. Vasculostatin (Vstat120) is the cleaved and secreted extracellular fragment of brain-specific angiogenesis inhibitor 1 (BAI1), a brain-specific receptor. To date, the therapeutic efficacy of Vstat120 delivery into established tumors has not been investigated. Here we tested the therapeutic efficacy of combining Vstat120 gene delivery in conjunction with OV therapy. We constructed RAMBO (Rapid Antiangiogenesis Mediated By Oncolytic virus), which expresses Vstat120 under the control of the herpes simplex virus (HSV) IE4/5 promoter. Secreted Vstat120 was detected as soon as 4 hours postinfection in vitro and was retained for up to 13 days after OV therapy in subcutaneous tumors. RAMBO-produced Vstat120 efficiently inhibited endothelial cell migration and tube formation in vitro (P = 0.0005 and P = 0.0184, respectively) and inhibited angiogenesis (P = 0.007) in vivo. There was a significant suppression of intracranial and subcutaneous glioma growth in mice treated with RAMBO compared to the control virus, HSVQ (P = 0.0021 and P < 0.05, respectively). Statistically significant reduction in tumor vascular volume fraction (VVF) and microvessel density (MVD) was observed in tumors treated with RAMBO. This is the first study to report the antitumor effects of Vstat120 delivery into established tumors and supports the further development of RAMBO as a possible cancer therapy.

Gene therapy via inducible nitric oxide synthase: a tool for the treatment of a diverse range of pathological conditions

Nitric oxide (NO(.)) is a reactive nitrogen radical produced by the NO synthase (NOS) enzymes; it affects a plethora of downstream physiological and pathological processes. The past two decades have seen an explosion in the understanding of the role of NO(.) biology, highlighting various protective and damaging modes of action. Much of the controversy surrounding the role of NO(.) relates to the differing concentrations generated by the three isoforms of NOS. Both calcium-dependent isoforms of the enzyme (endothelial and neuronal NOS) generate low-nanomolar/picomolar concentrations of NO(.). By contrast, the calcium-independent isoform (inducible NOS (iNOS)) generates high concentrations of NO(.), 2-3 orders of magnitude greater. This review summarizes the current literature in relation to iNOS gene therapy for the therapeutic benefit of various pathological conditions, including various states of vascular disease, wound healing, erectile dysfunction, renal dysfunction and oncology. The available data provide convincing evidence that manipulation of endogenous NO(.) using iNOS gene therapy can provide the basis for future clinical trials.

Gammadelta T-cells: potential regulators of the post-burn inflammatory response

Severe burn induces an immunopathological response that contributes to the development of a systemic inflammatory response (SIRS) and subsequent multiple organ failure. While, multiple immune cells type (T-cells, macrophages, neutrophils) are involved in this response, recent evidence suggests that a unique T-cell subset, gammadelta T-cells are central in the response to injury. While gammadelta T-cells represent only a small percentage of the total T-cell population, they display specific functional characteristics that uniquely position them in the immune/inflammatory axis to influence a number of important aspects of the body's response to burn. This review will focus on the potential regulator role of gammadelta T-cells in immunopathological response following burn and thereby their potential as therapeutic targets for affecting inflammation and healing.

(+)-Catechin inhibits tumour angiogenesis and regulates the production of nitric oxide and TNF-α in LPS-stimulated macrophages

The anti-angiogenic activity of (+)-catechin as well as its regulatory effect on the production of nitric oxide and TNFα were studied using in vivo and in vitro models. In vivo angiogenic activity was studied using B16F-10 melanoma cell-induced capillary formation in C57BL/6 mice. Administration of (+)-catechin significantly inhibited (36.09%) the number of tumour-directed capillaries induced by injecting B16F-10 melanoma cells on the ventral side of C57BL/6 mice. The cytokine profile in the serum of these animals showed a drastically increased level of proinflammatory cytokines such as IL-1β, IL-6, TNF-α, GM-CSF and the direct endothelial cell proliferating agent, VEGF. Administration of (+)-catechin could differentially regulate elevation of these cytokines. The differential elevation is further evidenced by the increased production of IL-2 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the B16F-10 injected, (+)-catechin-treated animals. In vitro L929 bioassay revealed the inhibition of TNF-α production by (+)-catechin treatment. In the rat aortic ring assay, (+)-catechin inhibited the microvessel outgrowth at non-toxic concentrations. (+)-Catechin at non-toxic concentrations (5—25 µg/ml) showed significant inhibition in the proliferation, migration and tube formation of endothelial cells, which are the key events in the process of angiogenesis. (+)-Catechin also showed inhibitory effect on VEGF mRNA levels in B16F-10 melanoma cells. (+)-Catechin inhibited the production of NO and TNF-α in LPS-stimulated primary macrophages. Taken together, these results demonstrate that (+)-catechin inhibits tumour-specific angiogenesis by regulating the production of pro- and anti-angiogenic factors such as pro-inflammatory cytokines, nitric oxide, VEGF, IL-2 and TIMP-1. These results also suggest that (+)-catechin could significantly inhibit nitrite and TNF-α production in LPS-stimulated macrophages.

Interferon-alpha promotes abnormal vasculogenesis in lupus: a potential pathway for premature atherosclerosis

Individuals with systemic lupus erythematosus (SLE) have a striking increase in premature atherosclerosis of unclear etiology. Accelerated endothelial cell apoptosis occurs in SLE and correlates with endothelial dysfunction. Endothelial progenitor cells (EPCs) and myelomonocytic circulating angiogenic cells (CACs) are crucial in blood vessel repair after vascular damage, and decreased levels or abnormal function of EPCs/CACs are established atherosclerosis risk factors. We investigated if vascular repair is impaired in SLE. We report that SLE patients display abnormal phenotype and function of EPCs/CACs. These abnormalities are characterized by significant decreases in the number of circulating EPCs (310 +/- 50 EPCs/mL of blood in SLE versus 639 +/- 102 in controls) and significant impairments in the capacity of EPCs/CACs to differentiate into mature ECs and synthesize adequate levels of the proangiogenic molecules vascular endothelial growth factor (VEGF) and hepatic growth factor (HGF). These abnormalities are triggered by interferon-alpha (IFN-alpha), which induces EPC and CAC apoptosis and skews myeloid cells toward nonangiogenic phenotypes. Lupus EPCs/CACs have increased IFN-alpha expression and their supernatants promote higher induction of IFN-inducible genes. Importantly, neutralization of IFN pathways restores a normal EPC/CAC phenotype in lupus. SLE is characterized by an imbalance between endothelial cell damage and repair triggered by type I IFNs, which might promote accelerated atherosclerosis.

Endothelial cell response to lactate: implication of PAR modification of VEGF

Angiogenesis, the process of formation of new blood vessels from pre-existing one, occurs in many physiological and pathological conditions, most of which are underlined by hypoxia and resultant accumulation of lactate. Although lactate is known to induce angiogenesis, the mechanism of its action on endothelial cells (ECs) is not known. The present study was designed to examine the response of ECs to lactate. Morphological analysis revealed that human umbilical vein endothelial cells (HUVECs) in culture respond to lactate by switching over to angiogenic phenotype concomitant with upregulation of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor-2 (VEGFR2) as determined by reverse transcription-PCR (RT-PCR). Apart from increase in the levels of VEGF protein as determined by ELISA, chorio allantoic membrane (CAM) assay using the cell extracts revealed that lactate also increased the angiogenic potency of VEGF. Isolated VEGF, when blotted and subsequently probed with anti-PAR antibody, revealed considerable reduction in poly-adenosyl ribosylation of VEGF associated with a significant decrease in the levels of NAD(+), in presence of lactate. Thus it appears that ECs respond to lactate by increasing the production of VEGF and modulating its angiogenic potency through poly-ADP ribosylation (PAR)-dependent mechanism and thereby switch over to angiogenic phenotype.

Isatins inhibit cyclooxygenase-2 and inducible nitric oxide synthase in a mouse macrophage cell line

Isatin is a versatile compound with a diversity of effects. We designed to investigate the inhibitory effect of isatin derivatives on lipopolysaccharide/interferon-gamma-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins, production of prostaglandin E(2) (PGE(2)), nitric oxide (NO), tumor necrosis factor (TNF-alpha), and their capacity to scavenge NO. Isatins inhibit TNF-alpha production and iNOS and COX-2 protein expression resulting on reduced levels of NO and PGE(2). Our results indicate isatin and it derivatives as inhibitors of iNOS and COX-2 enzymes, which might be used as anti-inflammatory and antitumoral agents.

Biological fate and clinical implications of arginine metabolism in tissue healing

Since its discovery in 1987, many biological roles (including wound healing) have been identified for nitric oxide (NO). The gas is produced by NO synthase using the dibasic amino acid L-arginine as a substrate. It has been established that a lack of dietary L-arginine delays experimental wound healing. Arginine can also be metabolized to urea and ornithine by arginase-1, a pathway that generates L-proline, a substrate for collagen synthesis, and polyamines, which stimulate cellular proliferation. Herein, we review subjects of interest in arginine metabolism, with emphasis on the biochemistry of wound NO production, relative NO synthase isoform activity in healing wounds, cellular contributions to NO production, and NO effects and mechanisms of action in wound healing.

Reactive oxygen species drives myocardial angiogenesis?

Neovascularization, the natural physiological process of formation of new blood vessels, is extremely important for ameliorating the function of the heart that undergoes ischemic stress. This process is potentially important for the treatment of ischemic heart and limb diseases, which includes formation of capillaries (angiogenesis) and collateral arteries. Ischemia or coronary artery occlusion induces vascular endothelial growth factor (VEGF) in the experimental rat myocardial infarction model, and this molecule encourages development of coronary collateral circulation and retention of the blood supply to the ischemic area. Restoration of the blood supply to the ischemic area prevents cardiomyocyte death and cardiac remodeling. Among the various triggers and enhancers of angiogenesis, hypoxic or ischemic preconditioning, as well as pharmacologic agents such as statin and resveratrol, have been identified as important stimuli for the induction of new vessel growth. It has already been demonstrated that the VEGF family and its receptor system is the fundamental regulator in the redox cell signaling of angiogenesis. This review article will focus on the role of reactive oxygen species in the process of myocardial angiogenesis.

Allyl isothiocyanate (AITC) and phenyl isothiocyanate (PITC) inhibit tumour-specific angiogenesis by downregulating nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha) production

Angiogenesis, a crucial step in the growth and metastasis of cancers, is initiated with vasodilation mediated by nitric oxide (NO). The pro-inflammatory cytokine, tumour necrosis factor-alpha (TNF-alpha), is a mediator of nitric oxide synthesis. We analyzed the effect of allyl isothiocyanate (AITC) and phenyl isothiocyanate (PITC) on serum NO as well as TNF-alpha level during angiogenesis. In vivo antiangiogenic activity was studied using B16F-10 melanoma cell-induced capillary formation in C57BL/6 mice. Intraperitoneal administration of AITC and PITC at a concentration of 25 microg/dose/animal significantly inhibited tumour-directed capillary formation. Treatment of AITC and PITC significantly downregulated serum NO as well as TNF-alpha level in angiogenesis-induced animals compared to untreated control animals. The in vitro antiangiogenic study, using rat aortic ring assay, showed that both AITC and PITC at non-toxic concentrations inhibited the production of proangiogenic factors from B16F-10 melanoma cells which was evident with the inhibition of microvessel outgrowth from aortic rings. Both AITC and PITC significantly inhibited sodium nitroprusside as well as TNF-alpha-induced microvessel outgrowth from rat aortic ring. Administration of AITC and PITC also significantly reduced NO and TNF-alpha production by LPS-stimulated macrophages both in vivo as well as in vitro. Bio-assay using serum of angiogenesis-induced animals and supernatant from LPS-stimulated macrophages clearly confirmed the downregulatory action of AITC and PITC on TNF-alpha production. These results clearly demonstrated that AITC and PITC inhibited tumour-specific angiogenesis by downregulating NO and TNF-alpha production.

Role of intracellular Ca2+ and calmodulin/MAP kinase kinase/extracellular signal-regulated protein kinase signalling pathway in the mitogenic and antimitogenic effect of nitric oxide in glia- and neurone-derived cell lines

To elucidate the mechanism of cell growth regulation by nitric oxide (NO) and the role played in it by Ca2+, we studied the relationship among intracellular Ca2+ concentration ([Ca2+]i), mitogen-activated protein kinases [extracellular signal-regulated protein kinase (ERK)] and proliferation in cell lines exposed to different levels of NO. Data showed that NO released by low [(z)-1-[2-aminiethyl]-N-[2-ammonioethyl]amino]diazen-1-ium-1,2diolate (DETA/NO) concentrations (10 microm) determined a gradual, moderate elevation in [Ca2+]i (46.8 +/- 7.2% over controls) which paralleled activation of ERK and potentiation of cell division. Functionally blocking Ca2+ or inhibiting calmodulin or MAP kinase kinase activities prevented ERK activation and antagonized the mitogenic effect of NO. Experimental conditions favouring Ca2+ entry into cells led to increased [Ca2+]i (189.5 +/- 4.8%), ERK activation and cell division. NO potentiated the Ca2+ elevation (358 +/- 16.8%) and ERK activation leading to expression of p21Cip1 and inhibition of cell proliferation. Furthermore, functionally blocking Ca2+ down-regulated ERK activation and reversed the antiproliferative effect of NO. Both the mitogenic and antimitogenic responses induced by NO were mimicked by a cGMP analogue whereas they were completely antagonized by selective cGMP inhibitors. These results demonstrate for the first time that regulation of cell proliferation by low NO levels is cGMP dependent and occurs via the Ca2+/calmodulin/MAP kinase kinase/ERK pathway. In this effect the amplitude of Ca2+ signalling determines the specificity of the proliferative response to NO possibly by modulating the strength of ERK activation. In contrast to the low level, the high levels (50-300 microm) of DETA/NO negatively regulated cell proliferation via a Ca2+-independent mechanism.

Comparison of ultrasound and electromagnetic field effects on osteoblast growth

This study compares the mechanisms of ultrasound (US) on osteoblast proliferation with those of pulsed electromagnetic field (PEMF), by different signal transduction pathway inhibitors. The cells were stimulated for 15 min under US or for 2 h under PEMF exposure. Twenty-four h after the beginning of stimulation, the cells were harvested and used for mitochondrial activity test (MTT) analysis. The results showed that there are different transduction pathways for US and PEMF stimulation that lead to an upgrade of osteoblast proliferation, although their pathways all lead to an increase in cytocolic Ca2+ and activation of calmodulin. These findings offer a biochemical mechanism to support the process of ultrasound and PEMF-induced enhanced healing of bone fractures.

Optimization of adenovirus-mediated endothelial nitric oxide synthase delivery in rat hindlimb ischemia

Adenovirus-mediated overexpression of endothelial nitric oxide synthase (eNOS) induces collateral artery development and substantially increases blood flow after induction of experimental acute hindlimb ischemia. However, the optimal technique of gene delivery for this or any other form of gene therapy in limb ischemia is still unknown. The purpose of this study was to determine the effect of the two most commonly used techniques, intra-arterial and intramuscular injection, on blood flow recovery, collateral artery development, and preservation of muscle mass. We compared intra-arterial injection under vascular isolation, intra-arterial injection under transient vascular occlusion, and intramuscular injection of phosphate buffered saline (PBS) or adenovirus encoding either the eNOS (AdeNOS) or LacZ (AdlacZ) gene after induction of acute hindlimb ischemia. Delivery of AdeNOS by both intra-arterial injection techniques increased eNOS activity (22.30 versus 10.56, P<0.01), blood flow (0.90+/-0.02 versus 0.69+/-0.07, P<0.001) and collateral artery development (17.56484 versus 13.74259, P<0.05) more than by intramuscular delivery. Intra-arterial injection under transient vascular occlusion led to better preservation of muscle mass, muscle architecture, and clinical ischemic index, but led to greater transgene expression in distant organs and contralateral limb muscles. Intra-arterial injection of AdeNOS under transient vascular occlusion is the optimal technique to reverse severe hindlimb ischemia in the rat. This is the first systematic comparison of different delivery techniques used in gene therapy of experimental hindlimb ischemia.

Angiogenesis and endothelial cell repair in renal disease and allograft rejection

This review discusses the concept that the turnover and replacement of endothelial cells is a major mechanism in the maintenance of vascular integrity within the kidney. CD133+CD34+KDR+ endothelial cell progenitor cells emigrate from the bone marrow and differentiate into CD34+KDR+ expressing cells, which are present in high numbers within the circulation. These progenitor cells are available for recruitment into normal or inflamed tissues to facilitate endothelial cell repair. In several forms of renal disease, proinflammatory insults mediate oxidative stress, senescence, and sloughing of endothelial cells. A lack of growth factors or an inefficient recruitment of endothelial cell progenitors results in hypoxic tissue injury and accelerates the process of chronic renal failure. Augmentation of vascular repair by the provision of growth factors such as vascular endothelial growth factor or by the transfer of progenitor cells directly into the kidney can be protective and prevent ongoing interstitial damage. In allografts, persistent injury results in excessive turnover of graft vascular endothelial cells. Moreover, chronic damage elicits a response that is associated with the recruitment of both leukocytes and endothelial cell progenitors, facilitating an overlapping process of inflammation and angiogenesis. Because the angiogenesis reaction itself is proinflammatory, this process becomes self-sustaining. Collectively, these data indicate that angiogenesis and endothelial cell turnover are important in renal inflammatory processes and allograft rejection. Manipulation of the response may have therapeutic implications to protect against injury and chronic disease processes.

Overexpression of nitric oxide synthases in tendon overuse

Tendon disorders with a chronic nature, including the rotator cuff, are extremely common, and represent a major clinical problem. Mechanical overload has been proposed as an important etiologic factor in tendinopathies. Nitric oxide (NO), a free radical produced by nitric oxide synthases (NOSs), is a potent regulator and stimulator of biological processes including tendon degeneration and healing. It is also involved in response to mechanical stimuli in different tissues. In an animal model of acutely injured tendon healing temporal and differential expression of NOS isoforms has been demonstrated, suggesting that different patterns of NOSs expression may have different biological functions. Therefore, we hypothesized that tendon overuse may result in a differential upregulation of NOSs, particularly iNOS. An animal model of supraspinatus tendon overuse was utilized, which consisted of treadmill running. A group of animals of the same strain and age subjected to normal cage activity were used as controls. Following a 4-week exercise protocol supraspinatus tendons were harvested, RNA was extracted, and subjected to competitive reverse transcription and polymerase chain reaction (RT-PCR) to determine the expression levels of inducible-, endothelial-, and neuronal-NOS isoforms (i-, e-, and nNOS). The mRNA expression of all three NOS isoforms increased in the supraspinatus tendons as a result of overuse exercise. iNOS and eNOS mRNA expression increased fourfold (p < 0.01), and there was an increase, but statistically not significant, in nNOS mRNA expression in the overused tendons when compared with the controls. This study is the first to show that NOS isoforms are upregulated in rotator cuff tendon as a result of chronic overuse, and suggests the involvement of nitric oxide in the response of tendon tissue to increased mechanical stress.

Nitric oxide and the vascular endothelium

The vascular endothelium synthesises the vasodilator and anti-aggregatory mediator nitric oxide (NO) from L-arginine. This action is catalysed by the action of NO synthases, of which two forms are present in the endothelium. Endothelial (e)NOS is highly regulated, constitutively active and generates NO in response to shear stress and other physiological stimuli. Inducible (i)NOS is expressed in response to immunological stimuli, is transcriptionally regulated and, once activated, generates large amounts of NO that contribute to pathological conditions. The physiological actions of NO include the regulation of vascular tone and blood pressure, prevention of platelet aggregation and inhibition of vascular smooth muscle proliferation. Many of these actions are a result of the activation by NO of the soluble guanylate cyclase and consequent generation of cyclic guanosine monophosphate (cGMP). An additional target of NO is the cytochrome c oxidase, the terminal enzyme in the electron transport chain, which is inhibited by NO in a manner that is reversible and competitive with oxygen. The consequent reduction of cytochrome c oxidase leads to the release of superoxide anion. This may be an NO-regulated cell signalling system which, under certain circumstances, may lead to the formation of the powerful oxidant species, peroxynitrite, that is associated with a variety of vascular diseases.

Upregulation of inducible nitric oxide synthase (iNOS) expression in faster-healing leg ulcers

OBJECTIVE

Chronic leg ulcers represent a growing clinical problem in the light of today's ageing population. Nitric oxide (NO), which is mostly produced by inducible nitric oxide synthase (iNOS) in healing wounds, exerts beneficial effects on many processes of healing, including bactericidal effects, angiogenesis, epithelialisation and ECM formation. This study sought to investigate whether iNOS expression in chronic leg ulcers can be correlated with the healing process.

METHOD

Sixteen patients with chronic leg ulcers were recruited and attempts were made to take punch biopsies at two separate time points (however, a second biopsy could not be obtained on seven patients). A linear healing rate was derived using the obtained ulcer area and perimeter. The iNOS levels in the biopsy samples were assessed using immunoblotting.

RESULTS

The mean linear healing rate of patients with high iNOS levels was significantly higher (p < 0.01) than that of patients with low iNOS levels. An incidental finding was that the linear healing rate was significantly higher (p < 0.05) post-biopsy than before biopsy in the same patients.

CONCLUSION

This study therefore shows for the first time that high iNOS levels are associated with higher healing rates and have the potential to be used in prognostication. This also opens the possibility of augmentation of ulcer healing through the manipulation of wound NO levels.

Nitric oxide: a newly discovered function on wound healing

Wound healing impairment represents a particularly challenging clinical problem to which no efficacious treatment regimens currently exist. The factors ensuring appropriate intercellular communication during wound repair are not completely understood. Although protein-type mediators are well-established players in this process, emerging evidence from both animal and human studies indicates that nitric oxide (NO) plays a key role in wound repair. The beneficial effects of NO on wound repair may be attributed to its functional influences on angiogenesis, inflammation, cell proliferation, matrix deposition, and remodeling. Recent findings from in vitro and in vivo studies of NO on wound repair are summarized in this review. The unveiled novel mechanisms support the use of NO-containing agents and/or NO synthase gene therapy as new therapeutic regimens for impaired wound healing.

Understanding the role of immune regulation in wound healing

The immune system plays an integral role in successful wound healing. In addition to contributing to host defenses and inflammation, immune cells are critical regulators of wound healing through the secretion of cytokines, lymphokines, and growth factors. We review the mechanisms by which the immune system regulates wound healing.

Nitric oxide and wound healing

Nitric oxide is a short-lived free radical that acts at the molecular, cellular, and physiologic level. Since its discovery almost 20 years ago it has proven itself as an important element in wound healing. This review highlights many of the important aspects of nitric oxide in wound healing, including a review of the basic biology of nitric oxide, its role as part of the cytokine cascade and as a promoter of angiogenesis, as well as its more recently elucidated role in apoptosis.

Inhibition of inducible isoforms of cyclooxygenase and nitric oxide synthase by flavonoid hesperidin in mouse macrophage cell line

Previous data have shown that a citrus flavanone, hesperidin possesses chemopreventive efficacies. We designed to investigate the inhibitory effect of hesperidin on lipopolysaccharide (LPS)-induced over-expression of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) proteins, over-production of prostaglandin E2 (PGE2) and nitric oxide (NO) using mouse macrophage cells. Treatment with hesperidin suppressed production of PGE2, nitrogen dioxide (NO2), and expression of iNOS protein. In the case of COX-2, hesperidin did not affect the protein level. Our data indicate hesperidin as a COX-2 and iNOS inhibitor, which might be related to the anti-inflammatory and anti-tumorigenic efficacies.

Proangiogenic function of CD40 ligand-CD40 interactions

Angiogenesis is a characteristic component of cell-mediated immune inflammation. However, little is known of the immunologic mediators of angiogenesis factor production. Interactions between CD40 ligand (CD40L) and CD40 have been shown to have pluripotent functions in inflammation, including the production of cytokines, chemokines, as well as the angiogenesis factor, vascular endothelial growth factor (VEGF), by endothelial cells. In this study we found that treatment of cultured human endothelial cells with an anti-CD40 Ab (to ligate CD40) resulted in the expression of several other angiogenesis factors, including fibroblast growth factor-2 and the receptors Flt-1 and Flt-4. To determine the proangiogenic effect of CD40L in vivo, human skin was allowed to engraft on SCID mice for 6 wk. These healed human skins express CD40 on resident endothelial cells and monocyte/macrophages, but not on CD20-expressing B cells. Skins were injected with saline, untransfected murine fibroblasts, or murine fibroblasts stably transfected with human CD40L. We found that the injection of CD40L-expressing cells, but not control cells, resulted in the in vivo expression of several angiogenesis factors (including VEGF and fibroblast growth factor) and a marked angiogenesis reaction. Mice treated with anti-VEGF failed to elicit an angiogenesis reaction in response to injection of CD40L-expressing cells, suggesting that the proangiogenic effect of CD40L in vivo is VEGF dependent. These observations imply that ligation of CD40 at a peripheral inflammatory site is of pathophysiological importance as a mediator of both angiogenesis and inflammation.

Prognostic value of serum IL-18 and nitric oxide activity in breast cancer patients at operable stage

Interleukin-18 (IL-18) is a multifunctional cytokine that was previously termed interferon-gamma-inducing factor. It has been suggested that serum IL-18 level may be used as a prognostic factor in some cancer types. Nitric oxide is a potent biologic molecule involved in the pathogenesis of cancer. In this study, we measured serum IL-18 and nitrate + nitrite levels in 56 patients with nonmetastatic breast cancer and 14 control subjects. Serum IL-18* and nitrate + nitrite** levels were significantly higher in patients with breast cancer when compared to the control subjects (*p < 0.05, **p < 0.001). Serum IL-18 levels were significantly higher in patients whose tumor size was greater than or equal to 5 cm when compared to patients whose tumor size was less than or equal to 2 cm (p < 0.05). Patients who were axillary lymph node negative (ALN) had lower serum IL-18 levels when compared to patients with positive ALN (p < 0.001). Serum IL-18 levels were significantly higher in patients with stage IIB or IIIA when compared to patients with stage I or IIA (p < 0.05). There was no significant difference in serum nitrate + nitrite levels in terms of age, tumor stage, estrogen receptor, and menopausal and ALN status (p > 0.05). In conclusion, serum IL-18 level may be a useful marker to predict prognosis of patients with breast cancer in complete remission after surgery. Long-term follow-up is required to clarify this hypothesis.

Nitric oxide synthase expression in human bladder cancer and its relation to angiogenesis

Nitric oxide (NO) is synthesized by the enzyme family of nitric oxide synthases (NOS) and plays an important role in tumor growth and angiogenesis. The expression of two of the NOS isoforms, the endothelial and inducible isoforms (eNOS and iNOS, respectively), were evaluated in bladder tissue from patients with transitional cell carcinoma (TCC). The specimens were procured from 58 patients with TCC and 14 cases of normal bladder mucosa were used as a control group. NOS immunohistochemistry was performed and microvessal density (MVD) was determined. iNOS specific proteins were found in 47 of 58 bladder cancer specimens but not in control bladder tissue. The endothelial cells in both normal urothelium and tumor tissue showed a highly positive eNOS immunostaining. The MVD was 39.3+/-19.5 and 29.3+/-10.5 in TCC positive and negative for iNOS, respectively ( P<0.01). A correlation between iNOS immunoreactivity and tumor grade in bladder carcinoma could not be verified. These results indicate that NO generation from iNOS in the malignant epithelium and from eNOS in tumor stroma play a important role in tumor angiogenesis.