Synthesis, storage, and release of vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) by human mast cells: implications for the biological significance of VEGF206

The Spontaneous Adhesion of BMMC onto Self-Assembled Peptide Nanoscaffold without Activation Inhibits Its IgE-Mediated Degranulation

Mast cells play a distinct role in the innate immune response. Engineered microenvironments for the express purpose of influencing mast cell activity will provide a novel means of designing biomaterials, as well as a means to systematically investigate mast cell biology in a 3D setting. Here, the effect of nanoscaffolds composed of self-assembling peptides, namely (RADA)₄ , on bone-marrow-derived murine mast cell (BMMC) activity is reported. Unlike most studies that stimulate mast cells to induce adhesion, this results show that BMMCs spontaneously adhere to the artificial nanoscaffold without initiating their activation. It is observed that the classical immunoglobulin (IgE) antigen-mediated degranulation of adhered BMMC is inhibited by the nanoscaffold, while non-IgE (A23187)-induced degranulation is unaffected. The inhibition of IgE-antigen-mediated degranulation is likely a result of inhibited molecular diffusion within the matrix; antigen diffusion, IgE-FcεRI complex shuttling, and/or formation of multiple IgE-FcεRI clusters may be physically hindered in the presence of the polyvalent nanofiber network. Moreover, the IgE/antigen-induced inflammatory cytokine tumor necrosis factor α release from adherent BMMCs is significantly reduced likely due to interaction with the nanofiber matrix. This work is considered the first step in quantifying mast cell activity in artificial matrices composed of self-assembling peptides.

Ischemic stroke in patients with POEMS syndrome: a case report and comprehensive analysis of literature

Background

POEMS syndrome is a rare multi-systemic disease characterized by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes. Arterial or venous thrombosis is a less-common complication of POEMS syndrome. Ischemic stroke has also been reported sporadically. However, the association between POEMS syndrome and ischemic stroke has not been entirely understood.

Methods

A case of ischemic stroke caused by cerebral vasculitis in a patient with POEMS syndrome was presented. Then a comprehensive review and analysis of the literature were performed.

Results

A total of 28 patients were identified. The common clinical manifestations of POEMS syndrome were rather non-specific in patients with ischemic stroke compared with those of patients without ischemic stroke. Twenty patients were found with multiple ischemic lesions (71.5%). In the 25 patients who had undergone the evaluation of cerebral arteries, nineteen patients (76.0%) were found with cerebral vasculopathy. Twelve patients (48.0%) had more than one cerebral artery involved. Ischemic events were documented in 8 patients even when they were undergoing all the therapy for ischemic stroke. Ten (55.6%) of the 18 patients who had survival data died within two years after stroke events.

Conclusion

Comprehensive analysis of literature revealed several trends in patients with ischemic stroke and POEMS syndrome including a low survival rate and a preponderance of cerebral vasculopathy and multiple cerebral arteries affected. Ischemic stroke may be a poor outcome predictor in patients with POEMS syndrome. Further researches focusing on a larger cohort may help in better characterizing and treating this rare complication of POEMS syndrome.

Bidirectional Mast Cell-Eosinophil Interactions in Inflammatory Disorders and Cancer

Human mast cells (MCs) and eosinophils were first described and named by Paul Ehrlich. These cells have distinct myeloid progenitors and differ morphologically, ultrastructurally, immunologically, biochemically, and pharmacologically. However, MCs and eosinophils play a pivotal role in several allergic disorders. In addition, these cells are involved in autoimmune disorders, cardiovascular diseases, and cancer. MCs are distributed throughout all normal human tissues, whereas eosinophils are present only in gastrointestinal tract, secondary lymphoid tissues, and adipose tissue, thymus, mammary gland, and uterus. However, in allergic disorders, MCs and eosinophils can form the "allergic effector unit." Moreover, in several tumors, MCs and eosinophils can be found in close proximity. Therefore, it is likely that MCs have the capacity to modulate eosinophil functions and vice versa. For example, interleukin 5, stem cell factor, histamine, platelet-activating factor (PAF), prostaglandin D2 (PGD2), cysteinyl leukotrienes, and vascular endothelial growth factors (VEGFs), produced by activated MCs, can modulate eosinophil functions through the engagement of specific receptors. In contrast, eosinophil cationic proteins such as eosinophil cationic protein and major basic protein (MBP), nerve growth factor, and VEGFs released by activated eosinophils can modulate MC functions. These bidirectional interactions between MCs and eosinophils might be relevant not only in allergic diseases but also in several inflammatory and neoplastic disorders.

Aged Lymphatic Vessels and Mast Cells in Perilymphatic Tissues

This review provides a comprehensive summary of research on aging-associated alterations in lymphatic vessels and mast cells in perilymphatic tissues. Aging alters structure (by increasing the size of zones with low muscle cell investiture), ultrastructure (through loss of the glycocalyx), and proteome composition with a concomitant increase in permeability of aged lymphatic vessels. The contractile function of aged lymphatic vessels is depleted with the abolished role of nitric oxide and an increased role of lymphatic-born histamine in flow-dependent regulation of lymphatic phasic contractions and tone. In addition, aging induces oxidative stress in lymphatic vessels and facilitates the spread of pathogens from these vessels into perilymphatic tissues. Aging causes the basal activation of perilymphatic mast cells, which, in turn, restricts recruitment/activation of immune cells in perilymphatic tissues. This aging-associated basal activation of mast cells limits proper functioning of the mast cell/histamine/NF-κB axis that is essential for the regulation of lymphatic vessel transport and barrier functions as well as for both the interaction and trafficking of immune cells near and within lymphatic collecting vessels. Cumulatively, these changes play important roles in the pathogenesis of alterations in inflammation and immunity associated with aging.

Are Mast Cells MASTers in Cancer?

Prolonged low-grade inflammation or smoldering inflammation is a hallmark of cancer. Mast cells form a heterogeneous population of immune cells with differences in their ultra-structure, morphology, mediator content, and surface receptors. Mast cells are widely distributed throughout all tissues and are stromal components of the inflammatory microenvironment that modulates tumor initiation and development. Although canonically associated with allergic disorders, mast cells are a major source of pro-tumorigenic (e.g., angiogenic and lymphangiogenic factors) and antitumorigenic molecules (e.g., TNF-α and IL-9), depending on the milieu. In certain neoplasias (e.g., gastric, thyroid and Hodgkin's lymphoma) mast cells play a pro-tumorigenic role, in others (e.g., breast cancer) a protective role, whereas in yet others they are apparently innocent bystanders. These seemingly conflicting results suggest that the role of mast cells and their mediators could be cancer specific. The microlocalization (e.g., peritumoral vs intratumoral) of mast cells is another important aspect in the initiation/progression of solid and hematologic tumors. Increasing evidence in certain experimental models indicates that targeting mast cells and/or their mediators represent a potential therapeutic target in cancer. Thus, mast cells deserve focused consideration also as therapeutic targets in different types of tumors. There are many unanswered questions that should be addressed before we understand whether mast cells are an ally, adversary, or innocent bystanders in human cancers.

Spatial distribution of mast cells around vessels and glands in human gastric carcinoma

The spatial distribution of mast cells inside the tumor stroma has been little investigated. In this study, we have evaluated tumor mast cells (MCs) distribution in gastric cancer through the analysis of the morphological features of the spatial patterns generated by these cells, including size, shape, and architecture of the cell pattern. The pattern of distribution of tryptase- and chymase-positive MCs around the blood vessels and gastric glands in human gastric adenocarcinoma samples was investigated by immunohistochemical techniques and by introducing a quantitative approach to characterize the spatial distribution of MCs. In human gastric cancer, both chymase-positive MC and vessels exhibited significant deviations from randomness for what it concerns their spatial relationship with gastric parenchyma. As indicated by cell-to-gland distances shorter than expected by chance, in grade II samples a preferential localization of chymase-positive MC near the gastric glands was observed. Interestingly, the same type of spatial association was exhibited by vessels in grade IV samples, where vessel-to-gland distances shorter than expected by chance were observed. These two findings allow to speculate about a sequence of events in which a subpopulation of MC is first recruited around gastric parenchyma to drive the subsequent development of a vascular support to the tissue.

The Effect of Smoking on Mast Cells Density and Angiogenesis in Chronic Periodontitis

BACKGROUND AND OBJECTIVE

Gingival bleeding reduction in smokers has been associated with decreased blood vessel density. The mechanism of suppressive effect of cigarette smoking on blood vessel density is not precisely defined. The aim of this study was to evaluate the impact of smoking on angiogenesis by assessing mast cells density and VEGF expression in chronic periodontitis.

MATERIALS& METHODS

52 paraffin embedded block of gingiva tissues with periodontitis obtained from 30 nonsmokers and 22 smokers undergoing flap surgery were examined immunohistochemically for VEGF expression. Mast cell counts was completed on toluidine blue stained slides. Exposure to cigarette smoking was calculated by the number of packs × year. Patients were classified into 4 groups based on the number of smoked cigarettes. The correlation between VEGF expression and mast cell counts was evaluated and compared in nonsmokers and smokers.

RESULTS

The mean number of mast cells (p=0.004) and average value of VEGF expression (p = 0.000) in nonsmokers was significantly higher than smokers. No correlation was noted between VEGF expression / mast cell counts and number of smoked cigarettes in four groups of smokers (p=0.29,0.12 , 0.20 and 0.11, respectively).

CONCLUSION

Mast cells and VEGF expression may account for suppressive effect of cigarette smoking on blood vessels in periodontitis.

Analysis of the presence and location of mast cells in periapical cysts and periapical granulomas

ABSTRACT Objective: The aim of the present study was to locate mast cells in chronic periapical lesions (granulomas and cysts) by using histochemical techniques and toluidine blue staining. Methods: A quantitative, descriptive, cross-sectional and retrospective research was performed. The sample was obtained from histopathological reports in the archives of the laboratory of surgical pathology of the University of Pernambuco between November 2014 and May 2015. Results: Sixteen cases of granuloma and 21 cases of periapical cysts were selected. The stained slides were analyzed by two examiners at different times, in a double-blind study. Mast cells were found in 13 (61.9%) of the periapical cyst cases, located in the capsule of the lesion. In the periapical granuloma cases, mast cells were found in eight cases (50%), located in the granulation tissue. Conclusion: Mast cells were detected in both cysts and periapical granuloma, located in the capsule and granulation tissue, respectively. Mast cells were more prevalent in periapical cysts than in periapical granuloma.

Mast cells in asthma--state of the art

Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.

Mast cells and their activation in lung disease

Mast cells and their activation contribute to lung health via innate and adaptive immune responses to respiratory pathogens. They are also involved in the normal response to tissue injury. However, mast cells are involved in disease processes characterized by inflammation and remodeling of tissue structure. In these diseases mast cells are often inappropriately and chronically activated. There is evidence for activation of mast cells contributing to the pathophysiology of asthma, pulmonary fibrosis, and pulmonary hypertension. They may also play a role in chronic obstructive pulmonary disease, acute respiratory distress syndrome, and lung cancer. The diverse mechanisms through which mast cells sense and interact with the external and internal microenvironment account for their role in these diseases. Newly discovered mechanisms of redistribution and interaction between mast cells, airway structural cells, and other inflammatory cells may offer novel therapeutic targets in these disease processes.

Live Staphylococcus aureus Induces Expression and Release of Vascular Endothelial Growth Factor in Terminally Differentiated Mouse Mast Cells

Mast cells have been shown to express vascular endothelial growth factor (VEGF), thereby implicating mast cells in pro-angiogenic processes. However, the mechanism of VEGF induction in mast cells and the possible expression of VEGF in fully mature mast cells have not been extensively studied. Here, we report that terminally differentiated peritoneal cell-derived mast cells can be induced to express VEGF in response to challenge with Staphylococcus aureus, thus identifying a mast cell–bacteria axis as a novel mechanism leading to VEGF release. Whereas live bacteria produced a robust upregulation of VEGF in mast cells, heat-inactivated bacteria failed to do so, and bacteria-conditioned media did not induce VEGF expression. The induction of VEGF was not critically dependent on direct cell–cell contact between bacteria and mast cells. Hence, these findings suggest that VEGF can be induced by soluble factors released during the co-culture conditions. Neither of a panel of bacterial cell-wall products known to activate toll-like receptor (TLR) signaling promoted VEGF expression in mast cells. In agreement with the latter, VEGF induction occurred independently of Myd88, an adaptor molecule that mediates the downstream events following TLR engagement. The VEGF induction was insensitive to nuclear factor of activated T-cells inhibition but was partly dependent on the nuclear factor kappa light-chain enhancer of activated B cells signaling pathway. Together, these findings identify bacterial challenge as a novel mechanism by which VEGF is induced in mast cells.

Mesenteric Traction Syndrome or Gut in Distress

The mesenteric traction syndrome (MTS) remains, seventeen years after its first designation as a distinct pathologic entity, an aspect of surgical practice that has received limited attention. Apart from its symptomatology, there is mostly speculation about its exact causes and pathophysiologic mechanisms.

Even though full-blown MTS is rather rare, the advent of laparoscopic surgery has indicated that there are different stages of stress associated with open abdominal surgery. Some evidence points to the involvement of mast cell derived vasoactive mediators and suggests possible pharmacologic management.

Recognition Sites for Microbes and Components of the Immune System on Human Mast Cells: Relationship to CD Antigens and Implications for Host Defense

Traditionally, mast cells (MCs) have been considered to play an important role in allergic disorders and helminth infections. More recently, MCs have been implicated in a variety of different infectious diseases including life-threatening disorders caused by viruses and bacteria. Apart from recognition through specific IgE, MCs are considered to recognize such bacteria and viruses via specific cell surface binding sites. In addition, MCs interact with diverse components and cells of the immune system and thereby may facilitate the targeting and the elimination of invading microbes in the tissues. The current article provides an overview on MC antigens contributing to microbe recognition and targeting as an important element of natural host-defense.

Sphingosine-1-Phosphate/Sphingosine-1-Phosphate Receptor 2 Axis Can Promote Mouse and Human Primary Mast Cell Angiogenic Potential through Upregulation of Vascular Endothelial Growth Factor-A and Matrix Metalloproteinase-2

Mast cells (MC) are present in most vascularized tissues around the vasculature likely exerting immunomodulatory functions. Endowed with diverse mediators, resident MC represent first-line fine-tuners of local microenvironment. Sphingosine-1-phosphate (S1P) functions as a pluripotent signaling sphingolipid metabolite in health and disease. S1P formation occurs at low levels in resting MC and is upregulated upon activation. Its export can result in type 2 S1P receptor- (S1PR2-) mediated stimulation of MC, further fueling inflammation. However, the role of S1PR2 ligation in proangiogenic vascular endothelial growth factor- (VEGF-) A and matrix metalloproteinase- (MMP-) 2 release from MC is unknown. Using a preclinical MC-dependent model of acute allergic responses and in vitro stimulated primary mouse bone marrow-derived MC (BMMC) or human primary skin MC, we report that S1P signaling resulted in substantial amount of VEGF-A release. Similar experiments using S1pr2-deficient mice or BMMC or selective S1P receptor agonists or antagonists demonstrated that S1P/S1PR2 ligation on MC is important for VEGF-A secretion. Further, we show that S1P stimulation triggered transcriptional upregulation of VEGF-A and MMP-2 mRNA in human but not in mouse MC. S1P exposure also triggered MMP-2 secretion from human MC. These studies identify a novel proangiogenic axis encompassing MC/S1P/S1PR2 likely relevant to inflammation.

Controlling Arteriogenesis and Mast Cells Are Central to Bioengineering Solutions for Critical Bone Defect Repair Using Allografts

Although most fractures heal, critical defects in bone fail due to aberrant differentiation of mesenchymal stem cells towards fibrosis rather than osteogenesis. While conventional bioengineering solutions to this problem have focused on enhancing angiogenesis, which is required for bone formation, recent studies have shown that fibrotic non-unions are associated with arteriogenesis in the center of the defect and accumulation of mast cells around large blood vessels. Recently, recombinant parathyroid hormone (rPTH; teriparatide; Forteo) therapy have shown to have anti-fibrotic effects on non-unions and critical bone defects due to inhibition of arteriogenesis and mast cell numbers within the healing bone. As this new direction holds great promise towards a solution for significant clinical hurdles in craniofacial reconstruction and limb salvage procedures, this work reviews the current state of the field, and provides insights as to how teriparatide therapy could be used as an adjuvant for healing critical defects in bone. Finally, as teriparatide therapy is contraindicated in the setting of cancer, which constitutes a large subset of these patients, we describe early findings of adjuvant therapies that may present future promise by directly inhibiting arteriogenesis and mast cell accumulation at the defect site.

Mast Cells Participate in Corneal Development in Mice

The development of the cornea, a highly specialized transparent tissue located at the anterior of the eye, is coordinated by a variety of molecules and cells. Here, we report that mast cells (MCs), recently found to be involved in morphogenesis, played a potentially important role in corneal development in mice. We show that two different waves of MC migration occurred during corneal development. In the first wave, MCs migrated to the corneal stroma and became distributed throughout the cornea. This wave occurred by embryonic day 12.5, with MCs disappearing from the cornea at the time of eyelid opening. In the second wave, MCs migrated to the corneal limbus and became distributed around limbal blood vessels. The number of MCs in this region gradually increased after birth and peaked at the time of eyelid opening in mice, remaining stable after postnatal day 21. We also show that integrin α4β7 and CXCR2 were important for the migration of MC precursors to the corneal limbus and that c-Kit-dependent MCs appeared to be involved in the formation of limbal blood vessels and corneal nerve fibers. These data clearly revealed that MCs participate in the development of the murine cornea.

The role of mast cell in tissue morphogenesis. Thymus, duodenum, and mammary gland as examples

Mast cells (MCs) are strategically located at host/environment interfaces like skin, airways, and gastro-intestinal and uro-genital tracts. MCs also populate connective tissues in association with blood and lymphatic vessels and nerves. MCs are absent in avascular tissues, such as mineralized bone, cartilage, and cornea. MCs have various functions and different functional subsets of MCs are encountered in different tissues. However, we do not' know exactly what is the physiological function of MC. Most of these functions are not essential for life, as various MC-deficient strains of mice and rats seems to have normal life spans. In this review article, we have reported and discussed the literature data concerning the role of MCs in tissue morphogenesis, and in particular their role in the development of thymus, duodenum, and mammary gland.

Mast cells and basophils in inflammatory and tumor angiogenesis and lymphangiogenesis

Angiogenesis, namely, the growth of new blood vessels from pre-existing ones, is an essential process of embryonic development and post-natal growth. In adult life, it may occur in physiological conditions (menstrual cycle and wound healing), during inflammatory disorders (autoimmune diseases and allergic disorders) and in tumor growth. The angiogenic process requires a tightly regulated interaction among different cell types (e.g. endothelial cells and pericytes), the extracellular matrix, several specific growth factors (e.g. VEGFs, Angiopoietins), cytokines and chemokines. Lymphangiogenesis, namely, the growth of new lymphatic vessels, is an important process in tumor development, in the formation of metastasis and in several inflammatory and metabolic disorders. In addition to tumors, several effector cells of inflammation (mast cells, macrophages, basophils, eosinophils, neutrophils, etc.) are important sources of a wide spectrum of angiogenic and lymphangiogenic factors. Human mast cells produce a large array of angiogenic and lymphangiogenic molecules. Primary human mast cells and two mast cell lines constitutively express several isoforms of angiogenic (VEGF-A and VEGF-B) and the two lymphangiogenic factors (VEGF-C and VEGF-D). In addition, human mast cells express the VEGF receptor 1 (VEGFR-1) and 2 (VEGFR-2), the co-receptors neuropilin-1 (NRP1) and -2 (NRP2) and the Tie1 and Tie2 receptors. Immunologically activated human basophils selectively produce VEGF-A and -B, but not VEGF-C and -D. They also release Angiopoietin1 that activates Tie2 on human mast cells. Collectively, these findings indicate that human mast cells and basophils might participate in the complex network involving inflammatory and tumor angiogenesis and lymphangiogenesis.

Potential effector and immunoregulatory functions of mast cells in mucosal immunity

Mast cells (MCs) are cells of hematopoietic origin that normally reside in mucosal tissues, often near epithelial cells, glands, smooth muscle cells, and nerves. Best known for their contributions to pathology during IgE-associated disorders such as food allergy, asthma, and anaphylaxis, MCs are also thought to mediate IgE-associated effector functions during certain parasite infections. However, various MC populations also can be activated to express functional programs--such as secreting preformed and/or newly synthesized biologically active products--in response to encounters with products derived from diverse pathogens, other host cells (including leukocytes and structural cells), damaged tissue, or the activation of the complement or coagulation systems, as well as by signals derived from the external environment (including animal toxins, plant products, and physical agents). In this review, we will discuss evidence suggesting that MCs can perform diverse effector and immunoregulatory roles that contribute to homeostasis or pathology in mucosal tissues.

Analysis of circulating vascular endothelial growth factor and its soluble receptors in patients with different forms of chronic urticaria

Background. Vascular endothelial growth factor (VEGF) is a powerful enhancer of vascular permeability and inflammatory response; however its significance in chronic urticaria is poorly recognised. Aim. To compare free circulating levels of VEGF and its soluble receptors (sVEGFR1 and VEGFR2) in patients with different forms of chronic urticaria. Methods. The concentrations of VEGF and its receptors in plateletpoor plasma (PPP)/plasma were measured using enzyme-linked immunosorbent assay in chronic urticaria: (1) chronic spontaneous urticaria (CSU) with positive autologous serum skin test (ASST), (2) CSU with negative response to ASST, (3) CSU with concomitant euthyroid Hashimoto's thyroiditis (CSU/Hashimoto), (4) delayed pressure urticaria (DPU), and the healthy subjects. Results. There were no significant differences in VEGF concentration in PPP between CSU groups and the healthy subjects. Contrary, VEGF concentration was significantly higher in DPU and CSU/Hashimoto patients as compared with the healthy subjects and CSU groups. Furthermore, VEGF value in CSU/Hashimoto patients during the remission was similar to that of the active period and significantly higher than the healthy subjects; VEGF concentration was significantly correlated with TSH. Plasma concentrations of sVEGF1 and sVEGF2 were similar in chronic urticaria patients and the healthy subjects. Conclusions. Increased free circulating VEGF concentration may result from the urticarial process itself as well as concomitant Hashimoto's thyroiditis.

Mast cells: potential positive and negative roles in tumor biology

Mast cells are immune cells that reside in virtually all vascularized tissues. Upon activation by diverse mechanisms, mast cells can secrete a broad array of biologically active products that either are stored in the cytoplasmic granules of the cells (e.g., histamine, heparin, various proteases) or are produced de novo upon cell stimulation (e.g., prostaglandins, leukotrienes, cytokines, chemokines, and growth factors). Mast cells are best known for their effector functions during anaphylaxis and acute IgE-associated allergic reactions, but they also have been implicated in a wide variety of processes that maintain health or contribute to disease. There has been particular interest in the possible roles of mast cells in tumor biology. In vitro studies have shown that mast cells have the potential to influence many aspects of tumor biology, including tumor development, tumor-induced angiogenesis, and tissue remodeling, and the shaping of adaptive immune responses to tumors. Yet, the actual contributions of mast cells to tumor biology in vivo remain controversial. Here, we review some basic features of mast cell biology with a special emphasis on those relevant to their potential roles in tumors. We discuss how using in vivo tumor models in combination with models in which mast cell function can be modulated has implicated mast cells in the regulation of host responses to tumors. Finally, we summarize data from studies of human tumors that suggest either beneficial or detrimental roles for mast cells in tumors.

The Role of VEGF in the Diabetic Patients Undergoing Endovascular Therapy of Symptomatic Aortic Valve Stenosis

The aim of this study was to explore changes in plasma vascular endothelial growth factor (VEGF) in aged patients who undergone transcatheter aortic valve implantation or balloon angioplasty for the treatment of aortic stenosis. Plasma VEGF was measured in subjects with diabetes mellitus type 2 (DM) (n=21, age 79.2±1.6 years) and in non-diabetic subjects (non-DM) (n=23, age 84.4±0.7 years), using an ELISA kit. Before the procedure plasma levels of VEGF were significantly lower in DM than in non-DM patients (P<0.05). Plasma VEGF significantly increased in both groups (DM and non-DM) 24 h (387±64 vs. 440±30 pg/ml, P<0.05) and 72 h (323±69 vs. 489±47 pg/ml, P<0.05) after the endovascular procedure. However, the VEGF in DM patients was significantly lower compared to non-DM subjects up to one month after the endovascular procedure (283±47 vs. 386±38 pg/ml, P<0.05). We conclude that increased plasma VEGF in aged patients associates with atherosclerotic aortic valve stenosis. In spite of that plasma VEGF in DM was constantly significantly lower than in non diabetic patients, both before and after the endovascular procedure, possibly reflecting a disturbance of angiogenic/anti-angiogenic balance in diabetes.

In vivo model for mastocytosis: A comparative review

Human mastocytosis are heterogeneous group of neoplastic diseases characterized by a different degree of uncontrolled mast cell (MC) proliferation and activation. Interestingly, human mastocytosis share several biological and clinical features with canine mast cell disorders, so called canine mast cell tumors (CMCTs). These CMCTs are the most common spontaneous cutaneous tumors found in dogs representing a valid model to study neoplastic mast cell disorders. It has been discovered that the pathological activation of c-Kit receptor (c-KitR), expressed by MCs, has been involved in the pathogenesis of neoplastic MC disorders. In this review we have focused on human mastocytosis in terms of: (i) epidemiology and classification; (ii) pathogenesis at molecular levels; (iii) clinical presentation. In addition, we have summarized animal models useful to study neoplastic MC disorders including CMCTs and murine transgenic models. Finally, we have revised therapeutic approaches mostly common in human and canine MCTs and novel tyrosine kinase inhibitors approved for CMCTs and recently translated in human clinical trials.

Mast cell function: a new vision of an old cell

Since first described by Paul Ehrlich in 1878, mast cells have been mostly viewed as effectors of allergy. It has been only in the past two decades that mast cells have gained recognition for their involvement in other physiological and pathological processes. Mast cells have a widespread distribution and are found predominantly at the interface between the host and the external environment. Mast cell maturation, phenotype and function are a direct consequence of the local microenvironment and have a marked influence on their ability to specifically recognize and respond to various stimuli through the release of an array of biologically active mediators. These features enable mast cells to act as both first responders in harmful situations as well as to respond to changes in their environment by communicating with a variety of other cells implicated in physiological and immunological responses. Therefore, the critical role of mast cells in both innate and adaptive immunity, including immune tolerance, has gained increased prominence. Conversely, mast cell dysfunction has pointed to these cells as the main offenders in several chronic allergic/inflammatory disorders, cancer and autoimmune diseases. This review summarizes the current knowledge of mast cell function in both normal and pathological conditions with regards to their regulation, phenotype and role.

Increased number of non-degranulated mast cells in pancreatic ductal adenocarcinoma but not in acute pancreatitis

Increasing evidence indicates that tumor microenvironment (TME) is crucial in tumor survival and metastases. Inflammatory cells accumulate around tumors and strangely appear to be permissive to their growth. One key stroma cell is the mast cell (MC), which can secrete numerous pro- and antitumor molecules. We investigated the presence and degranulation state of MC in pancreatic ductal adenocarcinoma (PDAC) as compared to acute ancreatitis (AP). Three different detection methods: (a) toluidine blue staining, as well as immunohistochemistry for (b) tryptase and (c) c-kit, were utilized to assess the number and extent of degranulation of MC in PDAC tissue (n=7), uninvolved pancreatic tissue derived from tumor-free margins (n=7) and tissue form AP (n=4). The number of MC detected with all three methods was significantly increased in PDAC, as compared to normal pancreatic tissue derived from tumor-free margins (p<0.05). The highest number of MC was identified by c-kit, 22.2&#x2213;7.5 per high power field (HPF) in PDAC vs 9.7&#x2213;5.1 per HPF in normal tissue. Contrary to MC in AP, where most of the detected MC were found degranulated, MC in PDAC appeared intact. In conclusion, MC are increased in number, but not degranulated in PDAC, suggesting that they may contribute to cancer growth by permitting selective release of pro-tumorogenic molecules.

Mast cells density positive to tryptase correlates with angiogenesis in pancreatic ductal adenocarcinoma patients having undergone surgery

Background. Literature data suggest that cells such as mast cells (MCs), are involved in angiogenesis. MCs can stimulate angiogenesis by releasing of several proangiogenic cytokines stored in their cytoplasm. In particular MCs can release tryptase, a potent in vivo and in vitro proangiogenic factor. Nevertheless few data are available concerning the role of MCs positive to tryptase in primary pancreatic cancer angiogenesis. This study analyzed MCs and angiogenesis in primary tumour tissue from patients affected by pancreatic ductal adenocarcinoma (PDAC). Method. A series of 31 PDAC patients with stage T_2-3N_0-1M₀ (by AJCC for Pancreas Cancer Staging 7th Edition) was selected and then underwent surgery. Tumour tissue samples were evaluated by means of immunohistochemistry and image analysis methods in terms of number of MCs positive to tryptase (MCDPT), area occupied by MCs positive to tryptase (MCAPT), microvascular density (MVD), and endothelial area (EA). The above parameters were related to each other and to the main clinicopathological features. Results. A significant correlation between MCDPT, MCAPT, MVD, and EA group was found by Pearson's t-test analysis (r ranged from 0.69 to 0.81; P value ranged from 0.001 to 0.003). No other significant correlation was found. Conclusion. Our pilot data suggest that MCs positive to tryptase may play a role in PDAC angiogenesis and they could be further evaluated as a novel tumour biomarker and as a target of antiangiogenic therapy.

The stealthy nano-machine behind mast cell granule size distribution

The classical model of mast cell secretory granule formation suggests that newly synthesized secretory mediators, transported from the rough endoplasmic reticulum to the Golgi complex, undergo post-transitional modification and are packaged for secretion by condensation within membrane-bound granules of unit size. These unit granules may fuse with other granules to form larger granules that reside in the cytoplasm until secreted. A novel stochastic model for mast cell granule growth and elimination (G&E) as well as inventory management is presented. Resorting to a statistical mechanics approach in which SNAP (Soluble NSF Attachment Protein) REceptor (SNARE) components are viewed as interacting particles, the G&E model provides a simple 'nano-machine' of SNARE self-aggregation that can perform granule growth and secretion. Granule stock is maintained as a buffer to meet uncertainty in demand by the extracellular environment and to serve as source of supply during the lead time to produce granules of adaptive content. Experimental work, mathematical calculations, statistical modeling and a rationale for the emergence of nearly last-in, first out inventory management, are discussed.

Low-dose diet supplement of a natural flavonoid, luteolin, ameliorates diet-induced obesity and insulin resistance in mice

SCOPE

Mast cells play important roles in diet-induced obesity and diabetes, and some synthetic mast cell stabilizers can improve related metabolic disturbances in mice. Luteolin (LU) is a potent natural mast cell stabilizer. However, a direct correlation between LU and these common metabolic diseases is not established.

METHODS AND RESULTS

Male C57BL/6 mice were fed low-fat diet, high-fat diet (HFD), HFD with 0.002 and 0.01% LU for 12 wk, respectively. Dietary LU suppressed HFD-induced body weight gain, fat deposition, and adipocyte hypertrophy. Meanwhile, glucose intolerance and insulin sensitivity was also improved. Interestingly, dietary LU ameliorated angiogenesis and associated cell apoptosis and cathepsin activity in epididymis adipose tissues, which is a critical mechanism that mast cells are involved in diet-induced obesity and diabetes. Further, we showed dietary LU reduced mast cell and macrophage infiltrations and inflammatory cytokine levels in epididymis adipose tissues. Finally, LU inhibited mast cell-derived IL-6 expression, which is a key cytokine that contributes to mast cell-associated metabolic derangements, and protein kinase C activator phorbol myristoyl acetate reversed the inhibitory effects.

CONCLUSIONS

As a natural flavonoid, low-dose diet supplement of LU ameliorates diet-induced obesity and insulin resistance in mice, suggesting a new therapeutic and interventional approach for these diseases.

The role of inflammatory cells in angiogenesis in multiple myeloma

Both innate and adaptive immune cells are involved in the mechanisms of endothelial cell proliferation, migration and activation, via production and release of a large spectrum of pro-angiogenic mediators, thus creating the specific microenvironment that favors increased rate of tissue vascularization. In this article, we focus on the immune cell component of the angiogenic process occurring during multiple myeloma progression. We also provide information on some anti-angiogenic properties of immune cells that may be applied for a potential pharmacological use as anti-angiogenic agents in the disease treatment.

Vascular endothelial growth factor (VEGF), mast cells and inflammation

Vascular endothelial growth factor (VEGF) is one of the most important inducers of angiogenesis, therefore blocking angiogenesis has led to great promise in the treatment of various cancers and inflammatory diseases. VEGF, expressed in response to soluble mediators such as cytokines and growth factors, is important in the physiological development of blood vessels as well as development of vessels in tumors. In cancer patients VEGF levels are increased, and the expression of VEGF is associated with poor prognosis in diseases. VEGF is a mediator of angiogenesis and inflammation which are closely integrated processes in a number of physiological and pathological conditions including obesity, psoriasis, autoimmune diseases and tumor. Mast cells can be activated by anti-IgE to release potent mediators of inflammation and can also respond to bacterial or viral antigens, cytokines, growth factors and hormones, leading to differential release of distinct mediators without degranulation. Substance P strongly induces VEGF in mast cells, and IL-33 contributes to the stimulation and release of VEGF in human mast cells in a dose-dependent manner and acts synergistically in combination with Substance P. Here we report a strong link between VEGF and mast cells and we depict their role in inflammation and immunity.

Serum endocan levels as a marker of disease activity in patients with Behçet disease

BACKGROUND

Endocan is a novel human endothelial cell-specific molecule. The central role of leukocytes and endothelial dysfunction in the development of Behçet disease (BD) led us to hypothesize that endocan might be a marker of this disease.

OBJECTIVE

We investigated the relationship between serum levels of endocan and disease activity in patients with BD.

METHODS

In all, 33 patients (16 active, 17 inactive) with BD and 35 healthy persons were included in the study. Endocan and C-reactive protein were measured in all subjects.

RESULTS

Patients with BD had significantly higher serum endocan levels. Mean serum levels of endocan were 1.29 ± 0.60 ng/mL (range: 0.58-2.99) in patients with BD and 0.75 ± 0.16 ng/mL (range: 0.48-1.21) in control subjects (P < .001). In patients with BD, serum endocan levels correlated moderately but significantly with C-reactive protein, erythrocyte sedimentation rate, and disease activity. Receiver operating characteristic curve analysis suggested that the optimum endocan level cut-off point for patients with BD was 0.87 ng/mL, with a sensitivity and specificity of 75.8% and 80%, respectively (area under curve 0.835, 95% confidence interval 0.738-0.932).

LIMITATIONS

The main limitation of our study is the relatively small sample size.

CONCLUSIONS

Circulating endocan may be a marker of BD activity.

Mast cells and macrophages exert beneficial and detrimental effects on tumor progression and angiogenesis

Mast cells and macrophages are critical regulators of inflammation and immunological response in the tumor microenvironment. Increased number of mast cells and macrophages have been reported to correlate with poor prognosis in numerous solid and hematological tumors. In contrast to their pro-tumorigenic role, mast cells and macrophages have shown also anti-tumorigenic effect in certain malignancies, for example by supporting cancer rejection. Thus, mast cells and macrophages can exert both detrimental and beneficial effects on tumor progression. Mast cell- and macrophages-derived growth factors able to promote tumor development and angiogenesis include TNF-α, TGF-β1, FGF-2, VEGF, PDGF, IL-8, osteopontin, and NGF. On the contrary, mast cell- and macrophages-produced cytokines that may participate in anti-tumor response include IL-1, IL-2, IL-4, IL-10, and IFN-γ. It is to note that mast cells and macrophages may also show beneficial and detrimental effects in the same cancer depending on the tumor stage.

The relationship between serum levels of angiogenin, bFGF, VEGF, and ocular involvement in patients with Behçet's disease

OBJECTIVES

The aim of this study was to investigate the possible role of angiogenin, vascular endothelial growth factor, (VEGF) and basic fibroblast growth factor (bFGF) in the pathogenesis of BD.

DESIGN AND METHODS

Sixty-five patients with BD and 21 healthy control subjects were included in the study, and serum angiogenin, bFGF, and VEGF concentrations were measured by using in-vitro enzyme immunoassay (ELISA) kits according to the manufacturer's instructions.

RESULTS

The median serum angiogenin level was significantly higher in patients with BD (391.8; range:151.6-594.8 pg/ml) than controls (298.8; range:241.9-449.6 pg/ml) (p = 0.001). The levels were similar in both ocular and non-ocular BD patients (p = 0.537). The mean serum bFGF level was higher in patients with BD (38.8 ± 12.3 pg/ml) than controls (33.2 ± 11.3 pg/ml); the median serum VEGF level was also higher in BD patients (239.7; range:53-991.3 pg/ml) than controls (189.4; range:53.6-357.9 pg/ml). But these differences were not statistically significant. Serum bFGF and VEGF levels were also not different statistically in ocular and non-ocular Behçet's patients. There was no statistically significant relationship between serum angiogenin, bFGF, and VEGF levels and the presence of active eye disease or anatomic location of uveitis. While there was a correlation of borderline significance in angiogenin levels between the patients with anterior uveitis and panuveitis (p = 0.053), we did not obtain any correlation between serum angiogenin, bFGF, and VEGF levels and the duration of BD.

CONCLUSIONS

This study suggests that angiogenin may be associated with pathophysiology of BD, and highlights the need of further investigation of the role of angiogenin, bFGF, and VEGF serum levels in BD susceptibility and its clinical manifestations.

Mast cells and vascular diseases

Mast cells are increasingly being recognized as effector cells in many cardiovascular conditions. Many mast-cell-derived products such as tryptase and chymase can, through their enzymic action, have detrimental effects on blood vessel structure while mast cell-derived mediators such as cytokines and chemokines can perpetuate vascular inflammation. Mice lacking mast cells have been developed and these are providing an insight into how mast cells are involved in cardiovascular diseases and, as knowledge increase, mast cells may become a viable therapeutic target to slow progression of cardiovascular disease.

Mast cell regulation of the immune response

Mast cells are well known as principle effector cells of type I hypersensitivity responses. Beyond this role in allergic disease, these cells are now appreciated as playing an important role in many inflammatory conditions. This review summarizes the support for mast cell involvement in resisting bacterial infection, exacerbating autoimmunity and atherosclerosis, and promoting cancer progression. A commonality in these conditions is the ability of mast cells to elicit migration of many cell types, often through the production of inflammatory cytokines such as tumor necrosis factor. However, recent data also demonstrates that mast cells can suppress the immune response through interleukin-10 production. The data encourage those working in this field to expand their view of how mast cells contribute to immune homeostasis.

Neurotensin and CRH interactions augment human mast cell activation

Stress affects immunity, but the mechanism is not known. Neurotensin (NT) and corticotropin-releasing hormone (CRH) are secreted under stress in various tissues, and have immunomodulatory actions. We had previously shown that NT augments the ability of CRH to increase mast cell-dependent skin vascular permeability in rodents. Here we show that NT triggered human mast cell degranulation and significantly augmented CRH-induced vascular endothelial growth factor (VEGF) release. Investigation of various signaling molecules indicated that only NF-κB activation was involved. These effects were blocked by pretreatment with the NTR antagonist SR48692. NT induced expression of CRH receptor-1 (CRHR-1), as shown by Western blot and FACS analysis. Interestingly, CRH also induced NTR gene and protein expression. These results indicate unique interactions among NT, CRH, and mast cells that may contribute to auto-immune and inflammatory diseases that worsen with stress.

Bevacizumab-induced oral mucositis in background of cutaneous plaque-type psoriasis

OBJECTIVE

To report the serial development of oral mucositis following infusion of bevacizumab in a young woman with a malignant brain tumor and history of cutaneous psoriasis.

CASE SUMMARY

A 29-year-old woman with a history of active cutaneous psoriasis and a malignant glioneuronal tumor was treated with bevacizumab for 2.5 years. With each infusion of bevacizumab, she developed oral mucositis within 36 hours. She received temozolomide as part of concurrent therapy with radiation and as maintenance therapy; it was discontinued after continuous therapy for 1.5 years. Bevacizumab 10 mg/kg was added after 7 cycles of maintenance temozolomide, as the tumor had minimal response and evidence of increased perfusion with angiogenesis on imaging studies. All medication, including temozolomide, was evaluated and eventually discontinued, with the exception of bevacizumab, which remained the drug suspected of causing the mucositis.

DISCUSSION

Oral mucositis is a frequent adverse effect of cytotoxic chemotherapy, but has not been reported with bevacizumab. The Naranjo probability scale indicated a probable adverse drug reaction. This likely indicates that bevacizumab is one of many drugs known to induce exacerbation of psoriatic disease. We speculate that oral mucositis developed as bevacizumab-induced generation of proinflammatory cytokines within the vascular endothelium, leading to mucosal damage and ulceration. In addition, interruption of reparative angiogenic pathways with bevacizumab likely contributed to the severity of mucositis.

CONCLUSIONS

Clinicians should be aware that bevacizumab can potentially exacerbate psoriatic disease.

Clinical and prognostic implications of low or high level of von Willebrand factor in patients with Waldenstrom macroglobulinemia

Acquired von Willebrand syndrome is described in patients with Waldenström macroglobulinemia (WM). Assessment of ristocetin cofactor activity (VWF:RCo) and von Willebrand factor (VWF) antigen (VWF:Ag) in 72 consecutive patients with WM showed a negative relation between VWF levels < 130 U/dL and both monoclonal immunoglobulin M concentration (mIgMC) and viscosity. Ten patients with VWF:RCo < 50 U/dL (< 40 for patients with blood group O) fulfilled the acquired von Willebrand syndrome criteria. They had higher mIgMC and viscosity. Reduction in mIgMC was associated with increase in VWF levels. The low VWF:RCo/VWF:Ag ratio suggested that high viscosity might be associated with increased shear force and cleavage of multimers. Surprisingly, 43 patients (59%) presented with high VWF:Ag (> 110 U/dL). They had higher bone marrow microvessel density and vascular endothelial growth factor expression on bone marrow mast cells. Five-year survival rates of patients with VWF:Ag < 110, between 110 and 250, and more than 250 U/dL were 96%, 71%, and 44%, respectively (P < .0001). High VWF:Ag was also a significant adverse prognostic factor for survival after first-line therapy (P < .0001), independently of the international scoring system. These results support systematic assessment of VWF in patients with WM. The adverse prognostic value of high VWF levels raises issues on interactions between lymphoplasmacytic cells, mast cells, and endothelial cells in WM.

A lack of correlation between mast cells, angiogenesis, and outcome in non-small cell lung cancer

Although a direct association between mast cells and cancer tumors is generally accepted, the exact nature of this relationship appears contradictory. The aim of this study was to clarify the effect of mast cells on tumor angiogenesis and outcome in Non-small cell lung cancer (NSCLC) patients. The tissue specimens evaluated were from patients with NSCLC who had undergone resection with curative intent at the Medical University of Bialystok Hospital. Of the 90 patients studied, 67 were men. Average age at surgery was 59.68 years. Study population included 29 cases of adenocarcinoma, 44 cases of squamous cell carcinoma, and 17 cases of large cell carcinoma. The authors counted mast cells and microvessels in tumor sections. Mast cells were observed in small groups around vessels and in the cancer parenchyma. At a magnification of 200×, the number of mast cells was 28.90 ± 16.6. Intramural microvessels in endothelial cells were found in small groups, mostly at the margin. At a magnification of 200×, the number of microvessels was 221.69 ± 120.36. Spearman correlation was observed in patients with adenocarcinoma, and also in patients with stage II disease. This study did not show correlation between mast cells count and survival rate, and correlation between microvessel count and survival rate. In this study, mast cells infiltration of the tumor islets was not associated with patients' survival. The authors did not find correlation between mast cells count and angiogenesis, except only in patients with adenocarcinoma, and in patients with stage II disease.

Mast cells promote the growth of Hodgkin's lymphoma cell tumor by modifying the tumor microenvironment that can be perturbed by bortezomib

Hodgkin's lymphoma is frequently associated with mast cell infiltration that correlates directly with disease severity, but the mechanisms underlying this relationship remain unclear. Here, we report that mast cells promote the growth of Hodgkin's tumor by modifying the tumor microenvironment. A transplantation assay shows that primary murine mast cells accelerate tumor growth by established Hodgkin's cell lines, and promote marked neovascularization and fibrosis. Both mast cells and Hodgkin's cells were sensitive to bortezomib, but mast cells were more resistant to bortezomib. However, bortezomib inhibited degranulation, PGE(2)-induced rapid release of CCL2, and continuous release of vascular endothelial growth factor-A from mast cells even at the concentration that did not induce cell death. Bortezomib-treated mast cells lost the ability to induce neovasculization and fibrosis, and did not promote the growth of Hodgkin tumor in vivo. These results provide further evidence supporting causal relationships between inflammation and tumor growth, and demonstrate that bortezomib can target the tumor microenvironment.

Association of mast cell-derived VEGF and proteases in Dengue shock syndrome

BACKGROUND

Recent in-vitro studies have suggested that mast cells are involved in Dengue virus infection. To clarify the role of mast cells in the development of clinical Dengue fever, we compared the plasma levels of several mast cell-derived mediators (vascular endothelial cell growth factor [VEGF], soluble VEGF receptors [sVEGFRs], tryptase, and chymase) and -related cytokines (IL-4, -9, and -17) between patients with differing severity of Dengue fever and healthy controls.

METHODOLOGY/PRINCIPAL FINDINGS

The study was performed at Children's Hospital No. 2, Ho Chi Minh City, and Vinh Long Province Hospital, Vietnam from 2002 to 2005. Study patients included 103 with Dengue fever (DF), Dengue hemorrhagic fever (DHF), and Dengue shock syndrome (DSS), as diagnosed by the World Health Organization criteria. There were 189 healthy subjects, and 19 febrile illness patients of the same Kinh ethnicity. The levels of mast cell-derived mediators and -related cytokines in plasma were measured by ELISA. VEGF and sVEGFR-1 levels were significantly increased in DHF and DSS compared with those of DF and controls, whereas sVEGFR-2 levels were significantly decreased in DHF and DSS. Significant increases in tryptase and chymase levels, which were accompanied by high IL-9 and -17 concentrations, were detected in DHF and DSS patients. By day 4 of admission, VEGF, sVEGFRs, and proteases levels had returned to similar levels as DF and controls. In-vitro VEGF production by mast cells was examined in KU812 and HMC-1 cells, and was found to be highest when the cells were inoculated with Dengue virus and human Dengue virus-immune serum in the presence of IL-9.

CONCLUSIONS

As mast cells are an important source of VEGF, tryptase, and chymase, our findings suggest that mast cell activation and mast cell-derived mediators participate in the development of DHF. The two proteases, particularly chymase, might serve as good predictive markers of Dengue disease severity.

Mast cells and inflammation

Mast cells are well known for their role in allergic and anaphylactic reactions, as well as their involvement in acquired and innate immunity. Increasing evidence now implicates mast cells in inflammatory diseases where they are activated by non-allergic triggers, such as neuropeptides and cytokines, often exerting synergistic effects as in the case of IL-33 and neurotensin. Mast cells can also release pro-inflammatory mediators selectively without degranulation. In particular, IL-1 induces selective release of IL-6, while corticotropin-releasing hormone secreted under stress induces the release of vascular endothelial growth factor. Many inflammatory diseases involve mast cells in cross-talk with T cells, such as atopic dermatitis, psoriasis and multiple sclerosis, which all worsen by stress. How mast cell differential responses are regulated is still unresolved. Preliminary evidence suggests that mitochondrial function and dynamics control mast cell degranulation, but not selective release. Recent findings also indicate that mast cells have immunomodulatory properties. Understanding selective release of mediators could explain how mast cells participate in numerous diverse biologic processes, and how they exert both immunostimulatory and immunosuppressive actions. Unraveling selective mast cell secretion could also help develop unique mast cell inhibitors with novel therapeutic applications. This article is part of a Special Issue entitled: Mast cells in inflammation.

Sonic Hedgehog on microparticles and neovascularization

Neovascularization represents a pivotal process consisting in the development of vascular network during embryogenesis and adult life. Postnatally, it arises mainly through angiogenesis, which has physiological and pathological roles in health and disease. Blood vessel formation results as tightly regulated multistep process which needs coordination and precise regulation of the balance of proangiogenic and antiangiogenic factors. Sonic Hedgehog (SHH), a morphogen belonging to Hedgehog (HH) family proteins, is implicated in a remarkably wide variety of process, including vessel development. Recent evidence demonstrate that, in addition to the classic factors, microvesicles (MVs), both microparticles (MPs) and exosomes, small vesicles released distinct cellular compartments, are involved in modulation of neovascularization. MPs generated from T lymphocytes undergoing both activation and apoptosis harbor at their surface SHH and play a crucial role in modulation of neovascularization. They are able to modulate the different steps implicated in angiogenesis process in vitro and to enhance postischemic neovascularization in vivo. As the consequence, we suggest that the MPs carrying SHH contribute to generation of a vascular network and may represent a new therapeutic approach to treat pathologies associated with failed angiogenesis.

Ocular Behçet disease: current therapeutic approaches

PURPOSE OF REVIEW

To alert physician to timely recognition and current treatment of recurrent hypopyon iridocyclitis or panuveitis in ocular Behçet disease (OBD).

RECENT FINDINGS

Interferon-α, rituximab, intravitreal triamcinolone, and biological response modifiers by tumor necrosis factor inhibitors such as infliximab and adalimumab are being used increasingly for the treatment of severe sight-threatening ocular inflammation including retinal vasculitis and cystoid macular edema (CME).

SUMMARY

Biological agents offer tremendous potential in the treatment of OBD. Given that OBD predominantly afflicts the younger adults in their most productive years, dermatologist, rheumatologist, internist, or general practitioners supervising patients with oculo-articulo-oromucocutaneous syndromes should be aware of systemic Behçet disease. Early recognition of ocular involvement is important and such patients should strongly be instructed to visit immediately an ophthalmologist, as uveitis management differs from extraocular involvements with high ocular morbidity from sight-threatening complications due to relapsing inflammatory attacks in the posterior segment of the eye. A single infliximab infusion should be considered for the control of acute panuveitis, whereas repeated long-term infliximab infusions were proved to be more effective in reducing the number of episodes in refractory uveoretinitis with faster regression and complete remission of CME.