Expression of Tie-2, angiopoietin-1, angiopoietin-2, ephrinB2 and EphB4 in pyogenic granuloma of human gingiva implicates their roles in inflammatory angiogenesis

Autologous Fat Grafting-A Panacea for Scar Tissue Therapy?

Scars may represent more than a cosmetic concern for patients; they may impose functional limitations and are frequently associated with the sensation of itching or pain, thus impacting both psychological and physical well-being. From an aesthetic perspective, scars display variances in color, thickness, texture, contour, and their homogeneity, while the functional aspect encompasses considerations of functionality, pliability, and sensory perception. Scars located in critical anatomic areas have the potential to induce profound impairments, including contracture-related mobility restrictions, thereby significantly impacting daily functioning and the quality of life. Conventional approaches to scar management may suffice to a certain extent, yet there are cases where tailored interventions are warranted. Autologous fat grafting emerges as a promising therapeutic avenue in such instances. Fundamental mechanisms underlying scar formation include chronic inflammation, fibrogenesis and dysregulated wound healing, among other contributing factors. These mechanisms can potentially be alleviated through the application of adipose-derived stem cells, which represent the principal cellular component utilized in the process of lipofilling. Adipose-derived stem cells possess the capacity to secrete proangiogenic factors such as fibroblast growth factor, vascular endothelial growth factor and hepatocyte growth factor, as well as neurotrophic factors, such as brain-derived neurotrophic factors. Moreover, they exhibit multipotency, remodel the extracellular matrix, act in a paracrine manner, and exert immunomodulatory effects through cytokine secretion. These molecular processes contribute to neoangiogenesis, the alleviation of chronic inflammation, and the promotion of a conducive milieu for wound healing. Beyond the obvious benefit in restoring volume, the adipose-derived stem cells and their regenerative capacities facilitate a reduction in pain, pruritus, and fibrosis. This review elucidates the regenerative potential of autologous fat grafting and its beneficial and promising effects on both functional and aesthetic outcomes when applied to scar tissue.

Pyogenic Granuloma in the Mandibular Anterior Gingiva: A Case Study

The oral cavity is frequently affected by gingival pyogenic granuloma (PG), a benign tumor that is known for its quick growth and tendency to hemorrhage. The clinical presentation, diagnostic procedure, and treatment of a patient with gingival pyogenic granuloma are all detailed in this case study. A female individual aged 25 years in otherwise good condition arrived with a sessile gingival tumor in the anterior mandibular region that was expanding quickly. During dental hygiene procedures, there was intermittent bleeding and discomfort related to the lesion. Based on histology analysis and clinical examination, PG was diagnosed. The course of treatment included surgical excision followed by a histological analysis to ensure total eradication. Appointments for follow-up revealed adequate healing and no indications of recurrence. This case study aims to demonstrate the need for prompt diagnosis, appropriate treatment, and diligent follow-up to effectively manage gingival pyogenic granuloma. Dental professionals can better treat patients and achieve better results with a thorough understanding of this common oral lesion and its management.

Oral Pyogenic Granuloma: A Narrative Review

Pyogenic granuloma (PG) is a benign vascular lesion found predominantly in the oral cavity. Characterized by rapid growth and propensity to bleed, PG presents diagnostic challenges due to its similarity and alarming proliferation. This narrative review synthesizes current knowledge on the epidemiology, etiopathogenesis, clinical manifestations, and management of oral PG, with emphasis on recent advances in diagnostic and therapeutic approaches. The epidemiology of the injury is meticulously analyzed, revealing a higher incidence in women and a wide range of ages of onset. It delves into the etiopathogenesis, highlighting the uncertainty surrounding the exact causal factors, although historical attributions suggest an infectious origin. It exhaustively analyzes the clinical and histopathological aspects of oral PG, offering information on its various presentations and the importance of an accurate diagnosis to guide effective treatment. It details treatment strategies, emphasizing the personalized approach based on individual patient characteristics. This comprehensive review consolidates current knowledge on oral PG, highlighting the need for further research to clarify its pathogenesis and optimize treatment protocols.

Comparative Evaluation of Efficacy and Safety of the Diode Laser (980 nm) and Sclerotherapy for the Treatment of Oral Pyogenic Granuloma

Background

Pyogenic granuloma (PG) is a tumor-like, non-neoplastic lesion of the soft tissue that commonly appears in the oral cavity. Various treatment modalities have been discussed, including surgical excision, cryosurgery, curettage, electrodessication, corticosteroid injection, sclerotherapy, and lasers. This observational retrospective study compared effectiveness between diode lasers and sclerotherapy for PG treatment.

Materials and Methods

From July 2016 to January 2021, data of oral PG cases treated with sclerotherapy and diode lasers were gathered. Patients were evaluated and categorized according to their gender, sex, site of lesions, size of lesions, number of sessions, details of side effects, details of the VAS (Visual Analogue Scale) on third postoperative day, response of treatment to individual groups, time required for complete resolution, and details of recurrence. Inferential statistical analysis was performed.

Results

We included 73 patients, of whom 43 and 30 received laser and sclerotherapy treatment, respectively. Compared with the sclerotherapy group, the laser group had less side effects including pain, edema, ulceration, ecchymosis, infections, and scarring. The difference in postoperative pain (VAS scale) between the groups was statistically significant (p-value 0.004). Complete remission was seen in the laser group, while 3 cases of the sclerotherapy group had no response (p-value −0.034). The laser group experienced greater recurrence than did the sclerotherapy group.

Conclusions

Both sclerotherapy with laser and 3% sodium tetradecyl sulfate are effective for treating oral PG. Sclerotherapy is more effective in preventing recurrence. In terms of side effects, diode lasers are superior to sclerotherapy.

Oral pyogenic granuloma: A case report and review of literature

Uvod: Pyogenic granuloma is a common non neoplastic growth in the oral cavity which is hyperplastic in nature. Various theories of etiopathogenesis have been suggested for pyogenic granuloma. It is commonly thought to be a response to various local irritants like calculus, foreign body material etc. It is hemorrhagic and often bleeds on touch. It usually causes local interference. Excisional biopsy is considered the treatment of choice for pyogenic granuloma followed by removal of the local irritants in order to avoid recurrence. This article presents a case of oral pyogenic granuloma in a 54-year-old patient in the gingiva extending up to the palate with a review of literature. Materials and methods: A thorough case history and clinical examination was done. A provisional diagnosis of pyogenic granuloma was given. Excisional biopsy was performed and the lesion was sent for histopathological evaluation. Result: Histopathological examination of the lesion confirmed the clinical diagnosis of pyogenic granuloma. Conclusion: Pyogenic granuloma is non neoplastic in nature and hence a detailed knowledge of this lesion is required in order to identify it in its early stage and to manage it appropriately before it causes any hindrance in normal routine functions.

Essential roles of EphrinB2 in mammalian heart: from development to diseases

EphrinB2, a membrane-tethered ligand preferentially binding to its receptor EphB4, is ubiquitously expressed in all mammals. Through the particular bidirectional signaling, EphrinB2 plays a critical role during the development of cardiovascular system, postnatal angiogenesis physiologically and pathologically, and cardiac remodeling after injuries as an emerging role. This review highlights the pivotal involvement of EphrinB2 in heart, from developmental cardiogenesis to pathological cardiac remodeling process. Further potential translational therapies will be discussed in targeting EphrinB2 signaling, to better understand the prevention and treatment of cardiovascular diseases.

A potassium-titanyl-phosphate laser is an efficacious tool in the treatment of pyogenic granulomas. A retrospective study in 28 patients

BACKGROUND AND OBJECTIVE

Pyogenic granuloma is a common benign vascular lesion of the skin and mucosa prone to ulceration and bleeding. Current therapeutic approaches include surgical excision, removal by means of electro caustic therapy, cryotherapy, and ablation with CO2 or vascular lasers. The purpose of this study was to investigate the efficacy of a 532 nm potassium-titanyl-phosphate laser (KTP-laser) for the treatment of pyogenic granulomas in terms of efficacy, advantages in clinical outcome, technique and associated side effects.

METHODS

In this retrospective study we report on the response of 28 consecutive patients with pyogenic granulomas at multiple locations on the skin after having been treated with a 532 nm KTP laser (532 nm AuraTM Star Pulse laser, Laserscope, CA, USA). Treatment was performed with a 2 mm handpiece and energy fluences of 35-60 J cm-2 and a laser pulse width of 50 ms or with a 1 mm handpiece and energy fluences of 200-240 J cm-2 and a laser pulse width of 50 ms. All patients were treated on an outpatient basis at the department of dermatology, Medical University of Vienna, Austria.

RESULTS

In all of the 28 patients treated, we were able to demonstrate both symptomatic and clinical clearing of the lesions with excellent cosmetic results after the treatment. In 25 of the 28 patients a single treatment was sufficient to obtain optimal results. In three patients a second treatment session was required due to the recurrence of the lesion. The procedure required only local anesthesia, and postoperative care was limited to the application of a topical antibiotic ointment. No postoperative complications such as increased pain or wound infection and only minimal scarring were observed.

CONCLUSIONS

This experience with excellent patient satisfaction suggests that treatment of pyogenic granulomas with the KTP laser is a safe, effective, and reasonable alternative to conventional therapy. As with many other limited interventions with this laser technology, the advantages include minimal postoperative pain, conservative site-specific minimally invasive surgeries and a very satisfactory cosmetic result with a high acceptance rate on the side of the patients.

Heterogeneous conceptualization of etiopathogenesis: Oral pyogenic granuloma

Oral pyogenic granuloma or granuloma pyogenicum is a conspicuous lesion. The word pyogenic granuloma is a misterm since the situation is not related with pus and histologically does not exemplify a granuloma. An oral pyogenic granuloma is obvious to involve the gingiva generally. Extragingivally, it can present on the buccal mucosa, lips, tongue, and palate. A report of trauma is prevalent in such sites. The pathogenesis of the lesion is still unclear, although it was initially supposed to be a botryomycosis infection. It is suggested that etiology of pyogenic granuloma was the reaction of tissues to minor injury or chronic irritation, thus open a pathway for the entrance of nonspecific microorganisms, although microorganisms are not often expressed within the lesion. Hence, this review recapitulates all diverse concepts of pathogenesis associated with this most often and most mysterious lesion of the oral cavity.

MicroRNA-454 is involved in regulating trophoblast cell proliferation, apoptosis, and invasion in preeclampsia by modulating the expression of ephrin receptor B4

Preeclampsia (PE) is a pregnancy-specific disorder representing a major cause for maternal and perinatal morbidity and mortality. The dysfunction of trophoblast cells plays an important role in the pathogenesis of PE. In recent years, microRNAs (miRNAs) have been suggested to play an important role in regulating trophoblast cell biological functions involved in the pathogenesis of PE. Accumulating evidence has showed that miR-454 plays an important role in regulating cell functions. However, whether miR-454 is involved in regulating cell functions of trophoblast cells during PE remains unclear. In this study, we found that miR-454 expression was significantly downregulated in placental tissues from PE patients. in vitro experiments showed that miR-454 overexpression significantly increased proliferation, inhibited apoptosis, and promoted invasion of trophoblast cells, whereas miR-454 inhibition markedly suppressed proliferation, increased apoptosis, and inhibited invasion of trophoblast cells. Interestingly, bioinformatics analysis predicted that ephrin receptor B4 (EPHB4), an important gene for regulating trophoblast cell function in PE, was a potential target gene of miR-454. Dual-luciferase reporter assay showed that miR-454 directly targeted the 3'-untranslated region of EPHB4. Real-time quantitative polymerase chain reaction and Western blot analysis demonstrated that miR-454 negatively regulated EPHB4 expression in trophoblast cells. Moreover, miR-454 expression was found inversely correlated with EPHB4 expression in placental tissues from PE patients. Importantly, EPHB4 overexpression partially reversed the promotion effect of miR-454 overexpression on trophoblast cell proliferation and invasion. Taken together, these findings demonstrate that miR-454 promotes the proliferation and invasion of trophoblast cells by inhibiting EPHB4 expression, and the decreased miR-454 expression may contribute to PE by promoting EPHB4 expression. Our study provides novel insights into understanding the molecular pathogenesis of PE.

The Periodontium as a Potential Cause of Orofacial Pain: A Comprehensive Review

Introduction:

Orofacial pain of periodontal origin has a wide range of causes, and its high prevalence and negative effect on patients' quality of life make intervention mandatory. This review provides a periodontological overview of the field of orofacial pain, focusing on the entities which involve the periodontal tissues and may be the cause of this pain or discomfort.

Methods:

The study comprised a literature search of these pathologies conducted in the MEDLINE/PubMed Database. Acute infectious entities such as gingival and periodontal abscesses are emergencies that require a rapid response. Periodontitis associated with endodontic processes, necrotizing periodontal disorders, desquamative gingivitis, gingival recession, and mucogingival herpetic lesions, cause mild to severe pain due to tissue destruction and loss. Other lesions that lead to periodontal discomfort include gingival enlargement and periodontal ligament strains associated with occlusal trauma, parafunctional habit and the impaction of food or foreign bodies.

Conclusion:

A range of therapeutic, pharmacological and surgical alternatives are available for the management of these injuries. However, the wide variety of causes of orofacial pain or periodontal discomfort may confuse the clinician during diagnosis and may lead to the wrong choice of treatment.

Correlation of Vascular and Inflammatory Index in Oral Pyogenic Granuloma and Periapical Granuloma - An Insight into Pathogenesis

INTRODUCTION

Angiogenesis is vital in the aetiology and pathogenesis of a number of pathological processes that include solid reactive lesions like pyogenic granuloma and chronic inflammatory disorders like periapical granuloma. Vascular Endothelial Growth Factor (VEGF) is a potent proangiogenic cytokine secreted by many cell types which present several pivotal functions in physiologic and pathologic angiogenesis.

AIM

The aim of the present study was to evaluate and compare the expression of VEGF in oral Pyogenic Granuloma (PG) and Periapical Granuloma (PAG) and also to correlate with the inflammatory cell infiltrate.

MATERIALS AND METHODS

Paraffin embedded tissue blocks of histologically diagnosed cases of PG and PAG, 20 of each were retrieved from the archives. The cases were selected randomly to evaluate the expression of VEGF marker and to assess the Mean Vascular Count (MVC) index and inflammation by Morphological Index (MI). The results were analysed using Unpaired t-test, Mann-Whitney U test and spearman correlation coefficient-test.

RESULTS

The PG showed higher expression of VEGF when compared to PAG with no significant difference in inflammation. PG showed positive correlation and PAG showed negative correlation between inflammation and VEGF expression.

CONCLUSION

Histologically similar PG and PAG are different not only by their clinical presentation but also by their mechanisms of formation and molecular sketch. Thereby raised expression of VEGF marker was established in PG emphasizing the fact that all histologically similar lesions need not have similar clinical course and molecular depiction.

EPHB4, a down stream target of IFN-γ/STAT1 signal pathway, regulates endothelial activation possibly contributing to the development of preeclampsia

PROBLEM

Preeclampsia is characterized by endothelial activation and excessive inflammation, of which interferon (IFN)-γ is a potent inducer. Eph receptor B4 (EPHB4) also involved in endothelial activation in inflammation. Their role and relationship in preeclampsia remain unclear.

METHOD OF STUDY

Intercellular adhesion molecular (ICAM)-1 was employed as the hallmark of endothelial activation. The serum levels of IFN-γ and the expression of EPHB4 and ICAM-1 were assessed by ELISA, qRT-PCR and WB, respectively. Primary human umbilical vein endothelial cells (HUVECs) were treated with IFN-γ of different concentration or for different times to determine the effect of IFN-γ on EPHB4 and ICAM-1 expression. Overexpression and shRNA constructs, chromatin immunoprecipitation (ChIP) and luciferase assays were conducted to clarify the regulation mechanism of IFN-γ/STAT1 on EPHB4 resulting in HUVECs activation. Endothelial-trophoblast co-culture model was used to illustrate the role of EPHB4 in the process of activated endothelial cells resisting trophoblast invasion.

RESULTS

IFN-γ, EPHB4 and ICAM-1 expression were elevated in preeclampsia. IFN-γ induced HUVECs activation through EPHB4 expression. ChIP and luciferase assays revealed that IFN-γ promoted EPHB4 transcription by STAT-1 binding to EPHB4 promoter. EPHB4 probably involved in resisting trophoblasts displacement by IFN-γ-activated HUVECs.

CONCLUSION

This study uncovered the character of EPHB4-regulating endothelial activation in the pathogenesis of preeclampsia.

EphrinB2/EphB4 pathway in postnatal angiogenesis: a potential therapeutic target for ischemic cardiovascular disease

Ischemic cardiovascular disease remains one of the leading causes of morbidity and mortality in the world. Proangiogenic therapy appears to be a promising and feasible strategy for the patients with ischemic cardiovascular disease, but the results of preclinical and clinical trials are limited due to the complicated mechanisms of angiogenesis. Facilitating the formation of functional vessels is important in rescuing the ischemic cardiomyocytes. EphrinB2/EphB4, a novel pathway in angiogenesis, plays a critical role in both microvascular growth and neovascular maturation. Hence, investigating the mechanisms of EphrinB2/EphB4 pathway in angiogenesis may contribute to the development of novel therapeutics for ischemic cardiovascular disease. Previous reviews mainly focused on the role of EphrinB2/EphB4 pathway in embryo vascular development, but their role in postnatal angiogenesis in ischemic heart disease has not been fully illustrated. Here, we summarized the current knowledge of EphrinB2/EphB4 in angiogenesis and their interaction with other angiogenic pathways in ischemic cardiovascular disease.

'Granuloma gravidarum': persistence in puerperal period an unusual presentation

Granuloma gravidarum (GG), an inflammatory lesion, develops in the oral mucosa of pregnant women in response to chronic low-grade irritants and hormonal factors. A persistent granuloma gravidarum post partum and appropriate management strategies are discussed. Patients must be encouraged to undergo regular dental check-ups during the gestational period. Simple oral hygiene measures are highly effective in combating most oral lesions encountered in pregnancy.

Oral pyogenic granuloma in hemophilia: a report of 2 cases

Pyogenic granulomas (PGs) are benign vascular lesions occurring in skin and mucous membranes, often secondary to trauma or chronic inflammation. Oral PGs have never been described previously in hemophilia. We describe 2 pediatric patients with hemophilia A, who developed PGs with inadequate factor therapy for bleeding. PG pathophysiology suggests an association with hemophilia given chronic vascular damage and low-grade inflammation at sites of bleeding in hemophilia patients. Knowledge about the occurrence of PGs in hemophilia patients is essential for prompt diagnosis and early institution of factor therapy, which in turn allows more rapid cessation of bleeding and lesion involution.

A Gray-purple Mass on the Floor of the Mouth: Gigantic Mucogingival Pyogenic Granuloma in a Teenage Patient

Pyogenic granuloma is defined as a benign neoplasm of vascular phenotype. This case describes the clinical and histopathological features of a gigantic mucogingival pyogenic granuloma, in a 14-year-old healthy black boy. This exophytic gray-purple mass, related to a toothpick injury, had more than twelve-month evolution on the anterior mandible involving lingual area besides to the floor of the mouth pressing the right salivary duct. Conservative excision was performed, followed by uncomplicated healing with no recurrence in two years. The histopathological examination reported a pyogenic granuloma (lobular capillary haemangioma). The authors provide a discussion of the presurgical differential diagnosis of the lesion. This case report presents an extremely uncommon location of a gigantic pyogenic granuloma, involving mucogingival complex and affecting the salivary outflow. This clinical manuscript may shed light on the controversies about possible mechanisms inducing oral pyogenic granuloma.

Sclerotherapy: a novel bloodless approach to treat recurrent oral pyogenic granuloma associated with port-wine stain

Pyogenic granuloma (PG) is a commonly occurring nonneoplastic inflammatory lesion in the oral cavity. Recent reports have demonstrated a rare association between skin PG and port-wine stain (PWS). Various treatment modalities such as complete excision, curettage, cryotherapy, chemical and electric cauterizations, lasers, and intralesional corticosteroids have been used to treat the lesion. In this case report, we present a novel method for the treatment of recurrent PG in a woman with concurrent presentation of PWS. In this patient, sclerotherapy with sodium tetradecyl sulfate (STS) was used as a treatment modality with successful resolution of the lesion. The authors thus conclude that sclerotherapy with STS can be an effective alternative for the treatment of recurrent PG associated with PWS.

Bi-directional relationship between pregnancy and periodontal disease

During pregnancy profound perturbations in innate and adaptive immunity impact the clinical course of a number of infectious diseases, including those affecting periodontal tissues. Conversely, it has been suggested that periodontal infections may increase the risk of adverse pregnancy outcomes. In this review, a summary of the literature associated with the bidirectional relationship between pregnancy and periodontal disease as well as the possible mechanisms behind this interaction were examined.

Angiogenesis and lymphangiogenesis in the spectrum of leprosy and its reactional forms

Background

Angiogenesis and lymphangiogenesis are the processes of neovascularization that evolve from preexisting blood and lymphatic vessels. There are few studies on angiogenesis and none on lymphangiogenesis in leprosy. Thus, the role of neovascularization in the pathophysiological mechanisms of the disease was studied across the spectrum of leprosy, its reactional states and its residual lesions.

Methodology/Principal Findings

Seventy-six biopsies of leprosy skin lesions and seven healthy controls were selected. Fifty-five serum samples were used for the detection of CD105 by ELISA. Histological sections were stained with antibodies against CD31 (blood and lymphatic vessels), D2-40/podoplanin (lymphatic vessels), and CD105/endoglin (neovessels). Microvessels were counted in 100 high-power fields (400x) and the number of vessels was evaluated in relation to the extension of the inflammatory infiltrate (0-3), to the bacillary index (0-6) and to the clinical forms. Angiogenesis, as marked by CD31 and CD105, was observed across the leprosy spectrum, compared with the controls. Additionally, there was a positive correlation between these markers with extension of the infiltrate (p <0.0001). For D2/40, lymphangiogenesis was observed in the tuberculoid form (p <0.0001). There was no statistical significance for values of CD105 detected in plasma by ELISA.

Conclusions/Significance

Angiogenesis is present across the spectrum of leprosy and in its reactional forms. The increase in the number of vessels, as detected by CD31 and CD105 staining, is related to the extension of the inflammatory infiltrate. Samples from reactional lesions have a higher number of CD31+ and CD105+ stained vessels, which indicates their involvement in the pathophysiological mechanisms of the reactional states. The regression of lesions is accompanied by the regression of neovascularization. Drugs inhibiting angiogenesis may be relevant in the treatment of leprosy, in addition to multidrugtherapy, and in the prevention of the development of reactions.

Pyogenic granuloma on the upper labial mucosa: a case report

Pyogenic granuloma is thought to represent an exuberant tissue response to a local irritation or trauma. It is a reactional response to constant minor trauma and it might be related to hormonal changes. Clinically, these lesions usually present as single nodules or sessile papules with smooth or lobulated surfaces. These may be seen in any size, from a few millimetres to several centimetres. Pyogenic granuloma of the oral cavity is known to involve the gingiva more commonly (75% of all the cases). An extragingival occurrence of pyogenic granuloma is rare. This paper has described an extragingival pyogenic granuloma which occurred on the upper labial mucosa in a 30 years old female patient.

Pyogenic granuloma of the gingiva: A misnomer? - A case report and review of literature

Pyogenic granuloma is a commonly occurring inflammatory hyperplasia of the skin and oral mucosa. It is not associated with pus as its name suggests and histologically it resembles an angiomatous lesion rather than a granulomatous lesion. It is known by a variety of names such as Crocker and Hartzell's disease, granuloma pyogenicum, granuloma pediculatum benignum, benign vascular tumor and during pregnancy as granuloma gravidarum. This tumor like growth is considered to be non-neoplastic in nature and it presents itself in the oral cavity in various clinical and histological forms. Due to its frequent occurrence in the oral cavity, especially the gingiva, this article presents a case report of a large pyogenic granuloma of the gingiva and its management, reviews the literature and discusses why the term "pyogenic granuloma" is a misnomer.

Assessment of angiogenic markers and female sex hormone receptors in pregnancy tumor of the gingiva

PURPOSE

Oral pregnancy tumors (OPTs) arise on the inflamed gingiva of women after the first trimester of pregnancy. The expression of angiogenic markers and female hormone receptors was assessed.

MATERIALS AND METHODS

Immunohistochemistry was used to analyze the expression of estrogen and progesterone receptors and the expression of angiogenic factors, such as vascular endothelial growth factor (VEGF) and its receptor, fibroblast growth factor (FGF), and hypoxia inducible factors 1α and 3α (HIF1α and HIF3α). Experimental groups included 9 OPTs, 10 oral pyogenic granulomas from nonpregnant women of the same age, and 9 oral pyogenic granulomas from postmenopausal women.

RESULTS

VEGF expression in stromal histiocytes and endothelial cells of small vessels was positively correlated in the OPT group (P < .05 by χ(2) test). VEGF receptor also was overexpressed in stromal histiocytes and endothelial cells of OPTs compared with oral pyogenic granulomas from nonpregnant and postmenopausal women (P < .005 by χ(2) test). No correlation was detected among estrogen and progesterone receptors, FGF and HIF1α and HIF3α (ER and PgR respectively) in the 3 experimental groups.

CONCLUSIONS

VEGF-associated angiogenesis is most likely involved in the pathogenesis of the lesion. These results imply that local inhibition of VEGF activity could be an adjuvant therapeutic approach for OPTs to control hemorrhage, which can be massive at the surgical excision of such lesions during pregnancy.

Henipavirus receptor usage and tropism

Nipah (NiV) and Hendra (HeV) viruses are the deadliest human pathogens within the Paramyxoviridae family, which include human and animal pathogens of global biomedical importance. NiV and HeV infections cause respiratory and encephalitic illness with high mortality rates in humans. Henipaviruses (HNV) are the only Paramyxoviruses classified as biosafety level 4 (BSL4) pathogens due to their extreme pathogenicity, potential for bioterrorism, and lack of licensed vaccines and therapeutics. HNV use ephrin-B2 and ephrin-B3, highly conserved proteins, as viral entry receptors. This likely accounts for their unusually broad species tropism, and also provides opportunities to study how receptor usage, cellular tropism, and end-organ pathology relates to the pathobiology of HNV infections. The clinical and pathologic manifestations of NiV and HeV virus infections are reviewed in the chapters by Wong et al. and Geisbert et al. in this issue. Here, we will review the biology of the HNV receptors, and how receptor usage relates to HNV cell tropism in vitro and in vivo.

[Neonatal botriomycoma of the tongue (a case report)]

INTRODUCTION

The botryomycoma is a benign tumor that develops as a response to a local trauma. Generally, it occurs in the fingers, the face and the oral cavity. It is often easily recognized. However, the diagnosis between this tumor and other oral tumors, whether benign or malignant, may be difficult in some cases. We report a particular case of a botryomycoma that occurred with no history of a trauma at an earlier age in the tongue, which is an unusual site for this tumor.

CASE REPORT

A 7-month-old infant presented with a polypoid and sessile swelling on the dorsal side of the tongue. This tumor gradually increased in size since birth. Clinically, the appearance of this mass with the gathered vessels inside was similar to that of a benign vascular tumor. A possibly malignant nature was not excluded. A complete resection under general anesthesia was performed. The histologic examination confirmed the diagnosis of pyogenic granuloma.

DISCUSSION

Pyogenic granuloma is a rare benign tumor which is most likely to occur between the age of 11 and 40. The most frequent location encountered for oral cavity is the gingiva. The tongue is rarely a site for its occurrence. Cutaneous pyogenic granuloma may have different aspect from mucosal type and thus may make the diagnosis difficult. Treatment consists on surgical excision and removal of etiological factors that may be source of recurrence.

Oral pyogenic granuloma: Various concepts of etiopathogenesis

Pyogenic granuloma or granuloma pyogenicum is a well-known oral lesion. The name pyogenic granuloma is a misnomer since the condition is not associated with pus and does not represent a granuloma histologically. Pyogenic granuloma of the oral cavity is known to involve the gingiva commonly. Extragingivally, it can occur on the lips, tongue, buccal mucosa, palate, and the like. A history of trauma is common in such sites. The etiology of the lesion is not known, though it was originally believed to be a botryomycotic infection. It is theorized that pyogenic granuloma possibly originates as a response of tissues to minor trauma and/or chronic irritation, thus opening a pathway for invasion of nonspecific microorganisms, although microorganisms are seldom demonstrated within the lesion. Pathogenesis of pyogenic granuloma is still debatable. Medline and PubMed databases were searched under the following key terms: Pathogenesis of oral pyogenic granuloma, pyogenic granuloma, and oral pyogenic granuloma. This search was limited to articles on human/animal studies which were published in English language. After reviewing the searched articles, the relevant articles were selected for the present review. Through this article, we have tried to summarize and present all the concepts of pathogenesis related to this most common and most mysterious oral lesion.

Essential roles of EphB receptors and EphrinB ligands in endothelial cell function and angiogenesis

Eph receptor tyrosine kinases and their Ephrin ligands represent an important signaling system with widespread roles in cell physiology and disease. Receptors and ligands in this family are anchored to the cell surface; thus Eph/Ephrin interactions mainly occur at sites of cell-to-cell contact. EphB4 and EphrinB2 are the Eph/Ephrin molecules that play essential roles in vascular development and postnatal angiogenesis. Analysis of expression patterns and function has linked EphB4/EphrinB2 to endothelial cell growth, survival, migration, assembly, and angiogenesis. Signaling from these molecules is complex, with the potential for being bidirectional, emanating both from the Eph receptors (forward signaling) and from the Ephrin ligands (reverse signaling). In this review, we describe recent advances on the roles of EphB/EphrinB protein family in endothelial cell function and outline potential approaches to inhibit pathological angiogenesis based on this understanding.

Oral pyogenic granuloma--a review of 215 cases in a South Indian Teaching Hospital, Karnataka, over a period of 20 years

INTRODUCTION

Pyogenic granuloma (PG) is a solitary, benign vascular growth. The precise cause for the development of pyogenic granuloma is unknown. It is believed, however, to be an exuberant tissue response to local irritation or trauma. Up to date, few studies have been carried out among Asians, particularly on the Indian subcontinent.

MATERIALS AND METHODS

Biopsy services were researched from 1989 to 2009. Two hundred-fifteen histologically confirmed PGs were retrieved and retrospectively analyzed for incidence, age, gender, site distribution, clinical presentation and histopathology. These cases were also evaluated for recurrence.

RESULTS AND DISCUSSION

Pyogenic granuloma accounted for 50.35% among reactive lesions in this study with a mean age of 34.27 years and a peak incidence in the third decade of life. PG was more common in females with a greater predilection for the maxillary gingivae (50.23%). Eighteen cases occurred in pregnant women. Clinically, PG occurred more frequently as pedunculated lesions (103). Gingival irritation and inflammation due to poor oral hygiene were the major precipitating factors. Histologically, PG presented a greater number of vascular channels of varied sizes, lined with plump endothelial cells, capillary budding, and chronic inflammatory cells, namely lymphocytes and plasma cells. Recurrence was seen in 14.88% of patients, predominantly in females, especially in the maxillary anterior region.

CONCLUSION

Among the reactive lesions, PG had the highest incidence. The frequency of pyogenic granuloma in the southern part of India was much higher compared to other studies. Additional epidemiological research is required to understand the frequency.

Pyogenic granuloma of unusual size with alveolar resorption in a 75-year-old patient

Pyogenic granuloma is an overzealously proliferative non-neoplastic lesion of connective tissue origin, found commonly in oral cavity and is secondary to chronic low grade local irritation, poor oral hygiene, and hormonal disturbances. The term is misnomer because a lesion is unrelated to infection. It is characterized by excessive and exuberant tissue repair response with varied inflammatory component. Since it is a benign lesion, choice of treatment is surgical excision with removal of underlying cause if any. This article aims at presenting a case of pyogenic granuloma in an extremely old patient which is unusual as it attained a very large size and also has caused mild resorption of underlying alveolar bone of mandible.

Pyogenic granuloma associated with periodontal abscess and bone loss - A rare case report

A diverse group of the pathologic process can produce the enlargement of soft tissues in the oral cavity and often present a diagnostic challenge. This soft tissue enlargement may represent a variation of the normal anatomic structure, inflammatory reaction, cyst, neoplasm, and developmental anomalies. A group of reactive hyperplasias, which develop in response to chronic recurring tissue injury that stimulates an excessive tissue repair response. The pyogenic granuloma (PG) is a reactive enlargement that is an inflammatory response to local irritation such as calculus, a fractured tooth, rough dental restoration, and foreign materials or hormonal (pregnancy tumor) and rarely associated with bone loss. This paper presents a rare case of PG associated with periodontal abscess and bone loss in a 30-year-old male.

Laser: a powerful tool for treatment of pyogenic granuloma

Lasers have opened a new door for the treatment of various disorders. Treatment of soft tissue intraoral mucosal growth by laser has profound effect on the patient acceptability taking the functional and aesthetic factor into consideration. The patient is able to get the outdoor treatment without the phobia of local anaesthetic and is out of the clinic in few minutes in contrast to the traditional method of surgical excision. Very few cases have been reported in literature regarding treatment of mucosal growth by soft tissue lasers. We present a case of recurrent pyogenic granuloma in a patient treated with an alternative approach, that is, diode laser, without the use of anaesthesia, sutures, anti-inflammatory drugs, or analgesics. The diagnosis of this lesion is equally important for correct treatment planning.

Altered vascular expression of EphrinB2 and EphB4 in a model of oxygen-induced retinopathy

EphrinB2 ligands and EphB4 receptors are expressed on endothelial cells (EC) of arteries and veins, respectively, and are essential for vascular development. To understand how these molecules regulate retinal neovascularization (NV), we evaluated their expression in a model of oxygen-induced retinopathy (OIR). EphrinB2 and EphB4 were expressed on arterial and venous trunks, respectively, and on a subset of deep capillary vessels. EphB4 expression was reduced following hyperoxia, while ephrinB2 expression remained unaltered. In addition, a subset of EphB4-positive veins regressed in a caspase-3-dependent manner during hyperoxia. Arteriovenous malformations were also observed with loss of arterial-venous boundaries. Finally, both ephrinB2 and EphB4 were expressed on a subset of neovascular tufts following hyperoxia. These data confirm the contribution of ECs from both venous and arterial origins to the development of retinal NV.

Angiogenesis in cutaneous disease: part II

This review will discuss the role of angiogenesis in specific cutaneous diseases. Scientific evidence now points to the role of angiogenesis in tumor development and many other cutaneous disorders. Angiogenesis is a complex process that involves angiogenic growth factors and inhibitors, many of which could be a potential target for pharmacologic intervention. Antiangiogenic agents have recently been applied to dermatologic diseases with promising efficacy.

LEARNING OBJECTIVES

After completing this learning activity, participants should be able to recognize cutaneous diseases where angiogenesis is likely to be an important factor, recognize scenarios where angiogenic therapy may be useful in conjunction with traditional therapies, and be able to use angiogenic-mediating agents in the treatment of dermatologic disease.

A mineralization-associated membrane protein plays a role in the biological functions of the peptide-coated bovine hydroxyapatite

BACKGROUND AND OBJECTIVE

Anorganic bovine mineral coated with a cell-binding peptide (P-15) is superior to anorganic bovine mineral alone in the treatment of periodontal osseous defects. However, the molecular interactions between P-15 and periodontal ligament fibroblasts remain unclear.

MATERIAL AND METHODS

We first compared the in vitro osteogenic activities between periodontal ligament fibroblasts cultured with anorganic bovine mineral alone and with the P-15/anorganic bovine mineral combination. We then harvested the periodontal ligament cell lysate, incubated it with various graft materials, and then washed it to remove unbound proteins. The bound proteins were eluted from graft materials and analyzed using electrophoresis, followed by mass spectrometry and then western blotting. Finally, a neutralizing antibody against one bound protein was added to the cell cultures to repeat the osteogenic assays to clarify its role in the in vitro effects of the P-15/anorganic bovine mineral combination.

RESULTS

Cells treated with P-15/anorganic bovine mineral were more viable and showed greater osteogenic activities than cells treated with anorganic bovine mineral alone and the no-graft control. Annexin II, a mineralization-associated protein, bound to P-15/anorganic bovine mineral significantly more than to anorganic bovine mineral alone. The addition of neutralizing antibody for annexin II decreased the osteogenic activities of the P-15/anorganic bovine mineral combination.

CONCLUSION

Annexin II of periodontal ligament fibroblasts interacted with the peptide of P-15, and was partially responsible for better in vitro osteogenesis in the P-15 graft.

Microsomal prostaglandin E synthase-1, ephrins, and ephrin kinases as suspected therapeutic targets in arthritis: exposed by "criminal profiling"

Feeding information obtained in one criminal case into the profile of another crime often helps to solve the latter. The literature on two different "crimes," namely, acute systemic inflammation and arthritis (including osteoarthritis [OA] and rheumatoid arthritis [RA] deals largely with the same "gang" of inflammatory mediators, such as prostaglandin (PG) E2. Early investigations suggested that microsomal PGE synthase-1 (mPGES-1; a terminal PGE2-synthesizing enzyme) plays a pivotal role in bacterial lipopolysaccharide (LPS)-induced systemic inflammation, but overlooked the possibility that the same enzyme could be involved in OA or RA. Later studies showed that mPGES-1 is indeed a key perpetrator in arthritic diseases, a fact that could have been predicted earlier by pooling the new knowledge about mPGES-1 into the profile of arthritic diseases. In this review, we analyze our recent study on the expression of erythropoietin-producing hepatocellular (Eph) receptor kinases and their ligands, ephrins, in LPS-induced systemic inflammation. By pooling these results together with literature data into the profile of RA, we conclude that Eph kinases and ephrins are prime suspects for being involved in the pathogenesis of RA. We further conjecture that the involvement of Eph kinases and ephrins may be realized via the induction of angiogenesis in the inflamed joint, promotion of leukocyte infiltration, and activation of the infiltrated cells. Studies to test this new hypothesis seem warranted, and our prediction is that the "smoking gun" will be found.

Putative dual role of ephrin-Eph receptor interactions in inflammation

Inflammation is associated with a decreased adhesion between endothelial cells in blood vessels and an increased adhesion of circulating leukocytes to vascular endothelium and to epithelia of internal organs. These changes lead to leukocyte extravasation and tissue transmigration. We propose that ephrins and Eph receptors play important, but underappreciated, signaling roles in these processes. At early stages of inflammation, EphA2 receptor and ephrin-B2 are overexpressed in endothelial and epithelial cells, thus leading to those events (expression of adhesion molecules on the cell surface and reorganization of the intracellular cytoskeleton) that cause cell repulsion and disruption of endothelial and epithelial barriers. At later stages of inflammation, expression of EphA1, EphA3, EphB3, and EphB4 on leukocytes and endothelial cells decreases, thus promoting adhesion of leukocytes to endothelial cells. Taking into consideration the abundance of ephrins and Eph receptors in tissues and the robustness of their signaling effects, the proposed involvement is likely to be substantial and may constitute a novel therapeutic target.

Vascular basis of mucosal color

Background

Besides the color of the teeth the color of the alveolar gingiva plays a crucial role in esthetic rehabilitation in dento-alveolar treatment. Whereas nowadays the color of the teeth can be determined exactly and individually, the specific influence of the red color of the gingiva on treatment has not been assessed yet. The aim of this study was to evaluate the vascularization as the basis for gingival esthetics.

Methods

Standardized photographs of defined areas of the alveolar gingiva in operated and non-operated patients were taken and assigned to groups with same characteristics after color comparisons. In addition, histologic and immunohistologic analyses of gingival specimens were performed for qualitative and quantitative assessment of vessels and vascularization. Finally, colors and number of vessels were correlated.

Results

Our results demonstrated three different constellations of colors of the alveolar gingiva in healthy patients. The operated patients could not be grouped because of disparate depiction. There was a clear correlation between color and vessel number in the alveolar gingiva.

Conclusion

Our investigations revealed the connections between vascularization and gingival color. Recommendations for specific change or even selection of colors based on the results cannot be given, but the importance of vascularly based incision lines was demonstrated.

Pyogenic granuloma of the oral cavity: Comparative study of its clinicopathological and immunohistochemical features

There are two histological types of pyogenic granuloma (PG) of the oral cavity: the lobular capillary hemangioma (LCH) and non-LCH type. The aim of the present study was to examine and compare the clinical features, etiological factors, diameter of vascular elements and immunohistochemical features of LCH and non-LCH histological types of PG to determine whether they are two distinct entities. Thirty cases of LCH and 26 cases of non-LCH PG were retrieved and retrospectively studied. Clinically, LCH PG occurred more frequently (66.4%) as sessile lesion whereas non-LCH PG occurred as pedunculated (77%). Non-LCH PG was associated more frequently (86.4%) with etiological factors. The lobular area of the LCH PG contained a greater number of blood vessels with small luminal diameter than did the central area of non-LCH PG. In the central area of non-LCH PG a significantly greater number of vessels with perivascular mesenchymal cells non-reactive for alpha-smooth muscle actin and muscle-specific actin was present than in the lobular area of LCH PG. The differences found in the present study suggest that the two histological types of PG represent distinct entities.

Direct chemotactic action of angiopoietin-1 on mesenchymal cells in the presence of VEGF

Angiopoietin-1 (Ang1) and its receptor, Tie2, play an important role in angiogenesis and vessel maturation. We previously reported that overexpression of Ang1 in MCF7 xenograft tumors facilitated vessel stabilization by mural cells, and that cultured SMC express Tie2. Here, we investigated whether Ang1 directly acts as a chemoattractant on mural cells or their precursors. In a Matrigel plug assay, neither Ang1 nor VEGF alone induced angiogenesis but together stimulated infiltration of non-endothelial cells that were CD31-negative, vimentin-positive and also positive for VEGFR-1 and Tie2. While negative for smooth muscle actin, reactivity for desmin suggests that the cells are mural cell precursors. VEGF treatment of cultured smooth muscle cells (SMC) upregulated Tie2 and allowed for Ang1-mediated phosphorylation of Tie2 and the AKT serine-threonine kinase. The combination of Ang1 and VEGF stimulated SMC migration in a Boyden chamber-type assay. In the presence of VEGF, Tie2 is upregulated on mural cells, allowing for a migratory response to Ang1. These findings support the view that Ang1, in concert with VEGF, can act directly on mural cells or their precursors to facilitate their recruitment to new blood vessels. This action may play an important role in vascular stabilization.

Suppression of angiogenesis and tumor growth by selective inhibition of angiopoietin-2

Angiopoietin-2 (Ang2) exhibits broad expression in the remodeling vasculature of human tumors but very limited expression in normal tissues, making it an attractive candidate target for antiangiogenic cancer therapy. To investigate the functional consequences of blocking Ang2 activity, we generated antibodies and peptide-Fc fusion proteins that potently and selectively neutralize the interaction between Ang2 and its receptor, Tie2. Systemic treatment of tumor-bearing mice with these Ang2-blocking agents resulted in tumor stasis, followed by elimination of all measurable tumor in a subset of animals. These effects were accompanied by reduced endothelial cell proliferation, consistent with an antiangiogenic therapeutic mechanism. Anti-Ang2 therapy also prevented VEGF-stimulated neovascularization in a rat corneal model of angiogenesis. These results imply that specific Ang2 inhibition may represent an effective antiangiogenic strategy for treating patients with solid tumors.

Syndecan-1 up-regulated by ephrinB2/EphB4 plays dual roles in inflammatory angiogenesis

EphrinB2 and EphB4, its cognate receptor, are important in the vascular development of the mouse embryo. Their roles in human inflammatory angiogenesis, however, are not well understood. By examining hyperinflammatory lesions, we saw that ephrinB2 was predominantly expressed in macrophage-like cells and EphB4 in small venules. Because macrophages usually transmigrate through postcapillary venules during inflammation, we wanted to explore the downstream effects of EphB4 after binding to ephrinB2. By using cDNA microarray technique and following reverse transcriptase-polymerase chain reaction (RT-PCR), we found that syntenin and syndecan-1 were up-regulated in EphB4-positive endothelial cells dose dependently and time dependently after stimulation with preclustered ephrinB2. In vitro, ephrinB2 suppressed the angiogenic effects of basic fibroblast growth factor (bFGF) on EphB4-positive endothelial cells, partially due to syndecan-1's competition with fibroblast growth factor receptor (FGFR) for bFGF. However, ephrinB2 exhibited angiogenic effects in vivo, possibly due to an inflammation-associated enzyme-heparanase. The enzymes could convert the inhibitory effect of ephrinB2 on EphB4-positive endothelial cells to an activating effect by removing poorly sulfated side chains of up-regulated syndecan-1 ectodomain. Depending on the presence of heparanases, the roles of syndecan-1 may be opposite in different physiological settings.

Oral pyogenic granuloma in Jordanians: a retrospective analysis of 108 cases

PURPOSE

The purpose of the present study was to retrospectively analyze the clinicopathologic features and treatment of oral pyogenic granuloma in Jordanian patients.

PATIENTS AND METHODS

Information regarding 108 cases of pyogenic granuloma of the oral cavity that underwent biopsy were retrieved from the records of patients seen at the maxillofacial and periodontology units of the Faculty of Dentistry, Jordan University of Science and Technology, during an 11-year period from 1991 to 2001. Data were reviewed and analyzed for age, gender, site, treatment, and clinical and histopathologic features.

RESULTS

Patient ages ranged from 3 to 85 years (mean, 30 years), with the greatest degree of occurrence (26.8%) in the second decade. The male-to-female ratio was 1:1.7. The mean age for females age was higher than that for males. The most frequently involved site was the gingiva (44.4%); other sites were the lips, tongue, buccal mucosa, and palate. Gingival pyogenic granulomas were more prevalent in the maxilla than in the mandible, with the anterior region of both jaws being more commonly affected. The labiobuccal gingiva of both jaws was more commonly affected. The main complaint was bleeding (59.3%), and almost half of the lesions had a pedunculated base, with surface ulceration in 9.2% of cases. The mean greatest granuloma diameter was 10 mm. All lesions were surgically excised, with 5.8% of cases known to have recurred.

CONCLUSIONS

The clinicopathologic features of oral pyogenic granuloma in Jordanians are similar to those of other whites. In this series, we found that with surgical excision of pyogenic granuloma, there was a low recurrence rate.

Modulation of angiogenic functions in human macrophages by biomaterials

We examined the ability of polyvinylchloride (PVC), polytetrafluorethylene (PTFE) and tissue culture polystyrene (TCPS) to affect angiogenic functions in human monocyte-derived macrophages by measuring the mRNA expression of genes encoding angiogenic and anti-angiogenic molecules including basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1) and thrombospondin-1 (Tsp-1). The angiogenic activity of the corresponding macrophage conditioned media (CM) was measured by the proliferation of endothelial cells and the sprouting of new capillaries from fragments of human placental blood vessels. We determined that bFGF was not expressed in macrophages while VEGF and Tsp-1 mRNAs were expressed constitutively. Ang-1 was expressed in macrophages cultured up to 7 days on PTFE and TCPS independent of the culture stage. In contrast, macrophages cultured on PVC did not produce detectable amounts of Ang-1 mRNA after 7 days. CM from macrophages cultured either on PTFE or TCPS stimulated angiogenesis whereas CM from macrophages cultured on PVC inhibited it. The results demonstrate that polymers can cause differential expression of the angiogenic molecule Ang-1 in macrophages. They also induce different phenotypes of macrophages, which can either stimulate or inhibit angiogenesis suggesting a material-dependent influence on neovascularization.

Rat aorta-derived mural precursor cells express the Tie2 receptor and respond directly to stimulation by angiopoietins

Recent studies have implicated the Tie2 tyrosine-kinase receptor and its main ligands--angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2)--as crucial regulators of mural cell recruitment during angiogenesis. Angiopoietin-mediated activation of Tie2 promotes perivascular mural cell assembly, but the mechanisms regulating this process are poorly understood because differentiated mural cells do not have the Tie2 receptor, which is reportedly expressed only in endothelial cells. There is also no direct evidence that Tie2 activation results in production of mural cell chemoattractants by the endothelium. In the rat aorta model of angiogenesis, developing microvessels recruit mural cells from the intimal/subintimal layers of the aortic wall. Ang-1 and Ang-2 promote angiogenesis in this system, stimulating branching morphogenesis and mural cell assembly. Mural precursor cells (MPCs) isolated with a nonenzymatic method from the intimal aspect of the rat aorta were positive for smooth muscle cell markers (alpha-smooth muscle actin and calponin) and negative for endothelial markers (factor-VIII-related antigen and CD31). These cells responded chemotactically to Ang-1 and Ang-2, and secreted MMP-2 when treated with these factors. Western-blot analysis, immunocytochemistry and RT-PCR demonstrated that MPCs express the Tie2 receptor. Immunoprecipitation showed phosphorylation of MPC Tie2 on tyrosine residues upon stimulation with Ang-1 or Ang-2. Surface expression of Tie2 was further demonstrated by isolating Tie2+/alpha-smooth muscle actin+ MPCs from primary aortic outgrowths with anti-Tie2-IgG-coated magnetic beads. Immunostaining of the rat aorta confirmed expression of Tie2 not only in endothelial cells but also in nonendothelial mesenchymal cells located in the aortic intimal/subintimal layers, which are the source of MPCs. These data indicate that the aortic wall contains Tie2+ nonendothelial mesenchymal cells and suggest that Tie2-related recruitment of mural cells during angiogenesis may occur through angiopoietin-mediated direct stimulation of these cells.

Altered expression of angiopoietins during blood-brain barrier breakdown and angiogenesis

Angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) belong to a novel family of endothelial growth factors that function as ligands for the endothelial-specific receptor tyrosine kinase, Tie-2. Ang-1 reduces endothelial permeability of noncerebral vessels and has a major role in vascular stabilization and maturation, whereas Ang-2 is thought to be an endogenous antagonist of the action of Ang-1 at Tie-2. Expression of these ligands at the mRNA and protein level were studied during both blood-brain barrier (BBB) breakdown and cerebral angiogenesis occurring in the rat cortical cold-injury model by RT-PCR analysis and immunohistochemistry respectively, during a time course of 6 hours to 6 days. In addition, immunohistochemical detection of fibronectin was used to detect BBB breakdown at the lesion site and dual labeling was used to determine whether the vessels demonstrating BBB breakdown expressed endothelial Ang-1 or Ang-2. Endothelial Ang-1 and Tie-2 proteins were present in all cerebral vessels of normal brain including those of the choroid plexuses, whereas both these proteins as well as Ang-2 were present in choroid plexus epithelium and in ependymal cells, suggesting that angiopoietins have an autocrine effect on these cell types as well. In contrast, in the early phase after injury during the known period of BBB breakdown, increased Ang-2 mRNA and protein and decreased endothelial Ang-1 and Tie-2 proteins were observed. Two to 6 days after injury, the progressive increase in Ang-1 mRNA and protein and the decrease in Ang-2 coincided with cerebrovascular angiogenesis. Confocal microscopy showed colocalization of both Ang-1 and Ang-2 in endothelium of lesion vessels, and our observation of colocalization of Ang-1 and Ang-2 in polymorphonuclear leukocytes and macrophages has not been reported previously. This study demonstrates that Ang-1 is an important factor in maintaining normal homeostasis in the brain. Thus Ang-1 therapy may have therapeutic potential in reducing BBB breakdown and the ensuing edema after massive brain injury.