Infantile Hemangioma: Challenges, New Insights, and Therapeutic Promise

Arteriovenous fistula of the mandible: a case report

Intraosseous arteriovenous malformations (AVM) are uncommon high-flow vascular malformation that can affect the maxilla or mandible. AVM may present with aspecific and misleading signs and symptoms. The diagnosis is often accidental and bleeding may represent the first symptom. Radiographically, there are few characteristic features and misdiagnosis is easy. Here we report the case of a young male affected by arteriovenous fistula on the right side of the mandible initially misdiagnosed as a cystic lesion. The patient underwent transarterial embolization of the vascular malformation and subsequently the lesion was surgically removed. 1-year follow-up showed complete healing of the mandibular bone and absence of recurrence. Intraosseous arteriovenous malformations are rare entities. However, due to their harmfulness, both clinicians and radiologists must be aware of this type of lesion and should always consider them in the differential diagnosis of osteolytic lesions.

Probing phosphorylation events in biological membranes: The transducer function

The extracellular environment is sensed by receptors in the plasma membrane. Some of these receptors initiate cytoplasmic signaling cascades involving phosphorylation: the addition of a phosphate group to a specific amino acid, such as tyrosine, in a protein. Receptor Tyrosine Kinases (RTKs) are one large class of membrane receptors that can directly initiate signaling cascades through their intracellular kinase domains, which both catalyze tyrosine phosphorylation and get phosphorylated. In the first step of signaling, the ligands stabilize phosphorylation-competent RTK dimers and oligomers, which leads to the phosphorylation of specific tyrosine residues in the activation loop of the kinases. Here we discuss quantitative measurements of tyrosine phosphorylation efficiencies for RTKs, described by the "transducer function". The transducer function links the phosphorylation (the response) and the binding of the activating ligand to the receptor (the stimulus). We overview a methodology that allows such measurements in direct response to ligand binding. We discuss experiments which demonstrate that EGF is a partial agonist, and that two tyrosines in the intracellular domain of EGFR, Y1068 and Y1173, are differentially phosphorylated in the EGF-bound EGFR dimers.

Therapeutic advances of targeting receptor tyrosine kinases in cancer

Receptor tyrosine kinases (RTKs), a category of transmembrane receptors, have gained significant clinical attention in oncology due to their central role in cancer pathogenesis. Genetic alterations, including mutations, amplifications, and overexpression of certain RTKs, are critical in creating environments conducive to tumor development. Following their discovery, extensive research has revealed how RTK dysregulation contributes to oncogenesis, with many cancer subtypes showing dependency on aberrant RTK signaling for their proliferation, survival and progression. These findings paved the way for targeted therapies that aim to inhibit crucial biological pathways in cancer. As a result, RTKs have emerged as primary targets in anticancer therapeutic development. Over the past two decades, this has led to the synthesis and clinical validation of numerous small molecule tyrosine kinase inhibitors (TKIs), now effectively utilized in treating various cancer types. In this manuscript we aim to provide a comprehensive understanding of the RTKs in the context of cancer. We explored the various alterations and overexpression of specific receptors across different malignancies, with special attention dedicated to the examination of current RTK inhibitors, highlighting their role as potential targeted therapies. By integrating the latest research findings and clinical evidence, we seek to elucidate the pivotal role of RTKs in cancer biology and the therapeutic efficacy of RTK inhibition with promising treatment outcomes.

Rapid low-cost hyperspectral imaging system for quantitative assessment of infantile hemangioma

Hemangioma, the predominant benign tumor occurring in infancy, exhibits a wide range of prognoses and associated outcomes. The accurate determination of prognosis through noninvasive imaging modalities holds essential importance in enabling effective personalized treatment strategies and minimizing unnecessary surgical interventions for individual patients. The present study focuses on advancing the personalized prognosis of hemangioma by leveraging noninvasive optical sensing technologies by the development of a novel rapid hyperspectral sensor (image collection in 5 s, lateral resolution of 10 μm) that is capable of quantifying hemoglobin oxygenation and vascularization dynamics during the course of tumor evolution. We have developed a quantitative parameter for hemangioma assessment, that demonstrated agreement with the clinician's conclusion in 90% among all cases during clinical studies on six patients, who visited clinician from two to four times. The presented methodology has potential to be implemented as a supportive tool for accurate hemangioma diagnostics in clinics.

Prenatal ultrasound evaluation of fetal cutaneous hemangioma and related complications

OBJECTIVES

Congenital hemangiomas are rare benign vascular tumors but can lead to serious adverse pregnancy outcomes. Its prenatal diagnosis is a challenge. We explored the clinical applications of prenatal ultrasound for evaluating fetal cutaneous hemangioma and associated complications.

METHODS

A retrospective observational study was conducted comprising a population of pregnant women with fetal cutaneous hemangioma, the latter diagnosed by prenatal ultrasound, between January 2016 and December 2020. The clinical characteristics, sonographic images, complications, and pregnancy outcomes were documented and analyzed.

RESULTS

We identified 20 cases of fetal cutaneous hemangioma diagnosed by prenatal ultrasound and confirmed by postpartum examinations. Most hemangiomas were in the head and neck (55%), with either solid isoechoicity (25%) or solid mildly hyperechoic (25%), and well-circumscribed (80%) mass. Eight (40%) fetuses experienced complications, which often occurred in fetuses with large hemangiomas (67% with maximum diameter ≥5 cm; 100% with a volume ≥40 cm³). The most common complications were cardiac-related (88%), including elevated cardiothoracic area ratio, atrioventricular valve regurgitation, and fetal hydrops. A large hemangioma was usually associated with advanced gestational age and a fast hemangioma growth rate. In five (25%) cases, the pregnancy was terminated; these involved hemangioma of the head or neck. One newborn developed Kasabach-Merritt phenomenon, pulmonary hemorrhage and respiratory distress, and died 3 days after birth. Among the 14 (70%) fetuses that survived birth, all hemangiomas disappeared or regressed after treatments with propranolol, interventional surgery, or observed routinely.

CONCLUSIONS

Prenatal ultrasound examination can accurately diagnose fetal cutaneous hemangioma and related complications to facilitate appropriate management during the pregnancy.

RATIONALE

Prenatal diagnosis of cutaneous hemangiomas is a clinical challenge. Prenatal ultrasound examination could be a method to accurately diagnose and monitor these hemangiomas.

Infantile Hemangioma: A Cross-Sectional Observational Study

(1) Background: With an incidence of 4-10%, infantile hemangiomas (IH) are the most encountered benign tumors in infancy. Low birth weight (LBW), prematurity, female sex, multiple gestations, and family history of IH are some of the statistically proven risk factors for developing IH. The aim of our study was to evaluate the prevalence of IH in our clinic and its connection to maternal and perinatal factors. (2) Methods: We conducted a cross-sectional study, over three years (2020-2022), at the Clinical Hospital of Obstetrics and Gynecology, "Prof. Dr. P. Sârbu", in Bucharest, Romania. (3) Results: During this period, 12,206 newborns were born and we identified 14 infants with infantile hemangioma. In our study, the prevalence of infantile hemangioma was 0.11%. The prevalence of IH in pregnancies obtained through in vitro fertilization was 1%, in twin pregnancies it was 2.27%, and in those with placenta previa, it was 4.16%. (4) Conclusions: Our findings provide a solid image of the prevalence of IH in our country and underline that the development of IH is strongly connected to maternal and perinatal variables, such as: preterm newborns, in vitro fertilization, high blood pressure, anemia, hypothyroidism, placenta previa, and twin pregnancy.

MicroRNA-195-5p inhibits the progression of hemangioma via targeting SKI

Hemangioma (HA), which is characterized by aberrant endothelial cell proliferation in blood vessels, is a common tumor during infancy. MicroRNAs (miRNAs/miRs) collectively participate in the development of HA; however, the potential roles of miR-195-5p in HA are not completely understood. The aim of the present study was to investigate the roles of miR-195-5p in HA. In the present study, miR-195-5p was found to be downregulated in HA cells, such as the XPTS-1 human infantile hemangioma-derived endothelial cell line and the EOMA hemangioendothelioma cell line. Overexpression of miR-195-5p was shown to suppress HA cell viability, colony formation and proliferation, and induced HA cell apoptosis. Furthermore, miR-195-5p downregulated Bcl-2 expression and upregulated Bax and Bcl-2 expression levels. V-ski sarcoma viral oncogene homolog (SKI) was identified as a target of miR-195-5p. Co-transfection of miR-195-5p mimics and SKI 3'-untranslated region wild-type decreased HA cell luciferase activity. SKI overexpression alleviated the miR-195-5p-induced decrease in HA cell proliferation and increased HA cell apoptosis. In addition, the regulatory role of miR-195-5p on the expression of Bcl-2, Bax and poly(ADP-ribose) polymerase was reversed by SKI. Collectively, the results of the present study demonstrated that miR-195-5p suppressed HA progression and its effects were mediated via SKI. Therefore, the miR-195-5p/SKI axis may represent a novel therapeutic target for HA.

The flavonoid luteolin suppresses infantile hemangioma by targeting FZD6 in the Wnt pathway

Infantile hemangioma is the most common vascular tumor of childhood. It is characterized by clinical expansion of endothelial cells and promoted by angiogenic factors. Luteolin is a flavonoid compound that carries anti-cancer and anti-angiogenesis properties. The study aimed to investigate the effect of luteolin in treating infantile hemangioma. We first tested the effect of luteolin on cell proliferative potential and VEGFA expression in hemangioma-derived stem cells (HemSCs). We then examined the efficacy of systemic application of luteolin in a murine hemangioma model. We then identified the downstream factor regulated by luteolin in HemSCs and validated its causative relationship with knock-down method in both in vitro and in vivo models. We also investigated the protein expression change of this targeting factor in proliferating hemangiomas. Luteolin inhibited HemSC growth and suppressed VEGF-A expression in a dose-dependent manner. Luteolin inhibited microvessel formation and de novo vasculogenesis in the murine model. FZD6 was induced by luteolin and exerted the anti-angiogenesis effect in our tumor models. Lastly, FZD6 level was repressed in the clinical tissues of human proliferating hemangiomas. Luteolin is a promising new agent to treat infantile hemangioma. Targeting the Wnt pathway may represent a potential therapeutic strategic to inhibit angiogenesis in proliferating hemangiomas.

News on infantile haemangioma. Part 1: clinical course and pathomechanism

Currently, there is no doubt that the first choice of treatment for alarming infantile haemangiomas (IHs) is oral beta-blockers. However, research in this field remains active, as the pathogenesis of IH is still not completely elucidated. Furthermore, there are different approaches to the management of IHs with beta-blockers. In Part 1 of this review we will discuss the state-of-the-art evidence for IH with regard to (i) the definition, epidemiology, course, risk factors and sequelae, and (ii) the pathogenesis, focusing on genetic studies. This review will update the reader on the latest developments in the pathogenesis of IH. Furthermore, we hope this review will give more insight into risk factors and sequelae of IH, thereby contributing to better decisions in the clinical management of patients with IH. The therapy and evaluation of IHs will be discussed in Part 2 of this review.

Genetic and Environmental Risk Factors for Isolated Hemangiomas in Infants

The goal of this analysis is to identify risk factors for infantile hemangiomas (IH) to better delineate hemangioma predisposition. We analyzed live birth children with isolated cutaneous hemangioma that were reported to the Polish Registry of Congenital Malformations from across Poland between the years 1998 and 2016. Lower birthweight and gestational age were the most significant risk factors associated with IH. We also observed a trend for a higher risk of IH with a lower level of maternal and paternal education. Moreover, mothers with IH have a higher probability of having a child with IH compared to fathers. However, this association is only present when the child is female. Similarly, a higher risk of hemangioma in a female child is found among mothers having relatives of the first degree with IH, compared to fathers with a similar pedigree. Our results suggest the role of exogenous factors in the etiology of IH. The analysis of familial cases suggests a multifactorial model of inheritance. The study indicates that female gender is an important risk factor for the expression of familial IH. Potential interaction of genetic risk factors with exposure to female sex hormones may play a role in the development of IH.

Ulcerated Infantile Hemangioma of the Hard Palate: Diagnostic Treatment With Oral Propranolol

Infantile hemangiomas arising in the palate are rare. The authors describe a case of ulcerated infantile hemangioma of the hard palate with feeding difficulty. To our knowledge, this is the first reported case of immunohistochemically diagnosed palatal infantile hemangioma successfully treated using oral propranolol.

Change of serum cytokine profiles by propranolol treatment in patients with infantile hemangioma

Infantile hemangioma is a benign cutaneous tumor, which sometimes rapidly enlarges, causes cosmetic problem, destroys normal tissue, and possibly threatens life. Dye lasers, steroid administration, and watchful waiting had been the treatment options for infantile hemangioma, but in recent years propranolol therapy has become available. The mechanism underlying the action of propranolol, however, is still unknown. We hypothesized that cytokines whose expressions change before and during the treatment are responsible for the efficacy of the drug. This study aims to prove the hypothesis using patients' sera and membrane array. In this study, the serum cytokine concentrations of five patients with infantile hemangioma were measured using membrane array of 20 angiogenic cytokines. We compared them before and during propranolol treatment to identify the cytokines responsible for the effect of propranolol. Signals for angiogenin, epidermal growth factor (EGF), platelet-derived growth factor-BB (PDGF-BB), regulated on activation, normal T-cell expressed and secreted chemokine (RANTES), tissue inhibitor of metalloproteinases 1 (TIMP-1), and tissue inhibitor of metalloproteinases 2 (TIMP-2) were evident in all five cases before treatment. Furthermore, PDGF-BB was the only cytokine of which concentration was decreased during treatment with statistically significant difference. This report is a pilot study with a small number of samples, and further detailed research with increased number of samples is necessary. Nonetheless, our results suggest that PDGF-BB may be involved in the action of propranolol. In addition, its serum concentration can be utilized as a potential marker of the therapeutic effect.

miR‑139‑5p affects cell proliferation, migration and adipogenesis by targeting insulin‑like growth factor 1 receptor in hemangioma stem cells

Infant hemangioma is the most common benign tumor in infancy. The pathological development process of this tumor is separated into the proliferation period, the involution period and the composite period in which a few residual capillary-like vessels grow through the loose fibrofatty tissue. Previous studies have confirmed that insulin-like growth factor 1 (IGF-1) is able to facilitate the cell proliferation of hemangioma stem cells (HemSCs) and the differentiation of HemSCs into adipocytes. Additionally, studies have confirmed that microRNAs (miRs) may serve a crucial function in regulating the IGF-1 receptor (IGF-1R). miR-139-5p often functions as a tumor suppressor. The present study was designed to investigate the mechanism of miR-139-5p in HemSCs. Dual luciferase reporter results verified that IGF-1R is the target gene of miR-139-5p. miR-139-5p overexpression reduced IGF-1R expression, and miR-139-5p inhibition increased IGF-1R expression. Cell Counting Kit-8 and Transwell migration assays demonstrated that miR-139-5p overexpression may target IGF-1R to inhibit the proliferation in addition to the migration of HemSCs. Reverse transcription-quantitative PCR, oil red o staining and western blot analysis confirmed that miR-139-5p overexpression was able to reduce adipogen-esis in HemSCs via the IGF-1/IGF-1R pathway. In contrary, miR-139-5p inhibition substantially enhanced the proliferation, migration and adipogenesis of HemSCs. Overall, miR-139-5p is able to affect the IGF-1/IGF-1R pathway by regulating IGF-1R expression, which ultimately affects the proliferation, migration and adipogenesis of HemSCs.

Distribution analysis of infantile hemangioma or capillary malformation on the head and face in Japanese patients

Infantile hemangioma is one of the most common tumors in infancy. Delivery may be a clue for the trigger of infantile hemangioma formation in the head and face areas. In this study, we tried to plot localization of infantile hemangioma as well as capillary malformation on the head and face, and compared them to identify their characteristics and risk factors. The distribution of 104 lesions in 100 patients with infantile hemangioma was as follows: 32 lesions on the head, 12 on the forehead, 57 on the cheek and three in the jaw area. We could not find a statistically significant correlation of the distribution with three clinical subtypes (superficial, deep and mixed), sex or size of the lesions. However, the lesions in the jaw or chin areas were significantly less frequent than other areas (P = 0.0008 or 0.03, respectively). This tendency was not found in 40 patients with capillary malformation. Mechanical stress to jaw or chin areas may be less than other areas in normal cephalic delivery. Considering the emergence after birth and age-dependent involution of infantile hemangioma, we speculate that physiological events including perinatal hypoxia or mechanical stress during delivery as the trigger of hemangioma formation. Taken together, our results may reveal the contribution of mechanical stress to the trigger of infantile hemangioma, not capillary malformation, and may facilitate clinical differentiation between the two diseases by their localization. Further studies with an increased number of patients will be necessary to validate the finding.

Benzyl butyl phthalate (BBP) triggers the migration and invasion of hemangioma cells via upregulation of Zeb1

Hemangioma (HA) are tumors formed by hyper-proliferation of vascular endothelial cells. As a potential endocrine disrupting chemical (EDC), benzyl butyl phthalate (BBP) can mimic estrogen to disturb the estrogenic signals. Our present study investigated the potential roles of phthalates on the progression of HA and found that 100 nM BBP can significantly trigger the migration and invasion of HA cells, which was evidenced by the results that BBP can induce the expression of matrix metalloproteinase (MMPs) and vimentin. Further, BBP can increase the expression of Zeb1, one powerful transcription factor for cell migration and invasion. Targeted inhibition of Zeb1 blocked BBP induced cell migration. Mechanistically, BBP can increase the mRNA stability of Zeb1 via suppression of miR-655. Further, BBP can enhance the protein stability of Zeb1 via upregulation of ataxia telangiectasia mutated (ATM). Collectively, our present study revealed that BBP can trigger the migration and invasion of HA cells via upregulation of Zeb1.

A prospective study of topical carteolol therapy in Chinese infants with superficial infantile hemangioma

BACKGROUND/OBJECTIVE

To report our observations from a trial of the short-term effectiveness and safety of topical carteolol hydrochloride drops to treat infantile hemangiomas (IHs).

METHODS

From October 2012 to September 2015, the study recruited 349 children with superficial IHs. Participants were randomized to two groups: treatment (n = 224 who received 2% carteolol hydrochloride drops administered to the lesion surface twice daily) and observation (n = 125 who did not receive treatment). Therapy duration was 6 months.

RESULTS

The mean age at the beginning of treatment was 3.2 months. Treatment responses were categorized as class 1 (total regression), class 2 (partial regression or controlled growth), or class 3 (no response). Of infants receiving carteolol treatment, 10.7% (24 patients) were categorized as class 1, 72.3% (162 patients) as class 2, and 17.0% (38 patients) as class 3. Of infants in the observation group, 5.6% (7 patients) were categorized as class 1, 25.6% (32 patients) as class 2, and 68.8% (86 patients) as class 3. No adverse effects were noted during treatment.

CONCLUSION

Carteolol is an effective, safe topical treatment for superficial IHs. Carteolol may be used to treat proliferative superficial IHs, particularly in infants younger than 6 months.

Prenatal Risk Factors for PHACE Syndrome: A Study Using the PHACE Syndrome International Clinical Registry and Genetic Repository

The cause of PHACE syndrome is unknown. In a study of 218 patients, we examined potential prenatal risk factors for PHACE syndrome. Rates of pre-eclampsia and placenta previa in affected individuals were significantly greater than in the general population. No significant risk factor differences were detected between male and female subjects.

The expression and function of miR-424 in infantile skin hemangioma and its mechanism

Infantile hemangioma is the most common benign tumor in infants. Many studies have confirmed that basic fibroblast growth factor (bFGF) and its key receptor FGFR1 are highly expressed in hemangioma. Moreover, several miRNAs can regulate angiogenesis. In this regard, miR-424 often plays a role as tumor suppressor gene. This study was designed to investigate the mechanism of miR-424 in infantile skin hemangioma. Our results showed low expression of miR-424 in infantile skin hemangioma tissues, and that miR-424 overexpression downregulated FGFR1 expression in hemangioma-derived endothelial cells, while miR-424 inhibition upregulated FGFR1 expression. Luciferase reporter analysis confirmed that FGFR1 was a target gene of miR-424. CCK-8, flow cytometry, transwell migration and tube formation assays demonstrated that miR-424 overexpression inhibited cell proliferation, migration and tube formation, at least in part by blocking the bFGF/FGFR1 pathway. In contrast, miR-424 inhibition significantly enhanced these functions. Furthermore, miR-424 overexpression significantly inhibited ERK1/2 phosphorylation, whereas miR-424 inhibition enhanced ERK1/2 phosphorylation. In conclusion, miR-424 could suppress the bFGF/FGFR1 pathway, thereby inhibit ERK1/2 phosphorylation, and thus inhibit cell proliferation, migration and tube formation capabilities and the development of infantile skin hemangioma.

An update of 77 cases diagnosed as oral hemangiomas based on GLUT-1 positivity

OBJECTIVES

To evaluate cases diagnosed as "oral hemangiomas" based on the immunohistochemical expression of human glucose transporter protein (GLUT-1) and on histopathological features, and to investigate whether the classification proposed by the ISSVA was used correctly to classify these lesions.

MATERIAL AND METHODS

All cases stored in the archives of an Oral Pathology Service and diagnosed as "oral hemangiomas" were reviewed. Seventy-seven cases were analyzed regarding the expression of GLUT-1. GLUT-1(+) specimens were classified as true infantile hemangioma (IH) and GLUT-1(-) specimens were reclassified based on their histopathological features. The nomenclature of these lesions was evaluated and some cases were reclassified.

RESULTS

Only 26 (33.8%) of the specimens were indeed IHs. Among the GLUT-1(-) specimens, 20 (26.0%) were reclassified as pyogenic granulomas (PGs) and 31 (40.2%) as vascular malformations. Considering the previously applied nomenclature, only 47.5% of the cases initially diagnosed as "hemangiomas" were IHs. In the group of "capillary hemangiomas", most cases (56.2%) were PGs. Among the three "cellular hemangiomas", two were PGs and one was IH. Most (88.8%) "cavernous hemangiomas" were vascular malformations.

CONCLUSION

Careful and parameterized review of cases of vascular anomalies is necessary using auxiliary tools such as GLUT-1, since the exclusive use of histopathological findings might be insufficient to differentiate some anomalies.

CLINICAL RELEVANCE

Accurate clinical examination and the use of biomarkers such as GLUT-1 are essential for the diagnosis.

Transcriptional activation of Hedgehog pathway components in aggressive haemangioma

Infantile hemangioma is a vascular neoplasm and is one of the most common tumors diagnosed in young children. Although most hemangiomas are harmless and involute spontaneously, some show severe progression, leading to serious complications, such as high-output cardiac failure, ulcerations, compression of the trachea or deprivation amblyopia, depending on their size and localization. However, the pathogenesis and cause of hemangioma are largely unknown to date. The goal of this study was to identify markers that could predict hemangiomas with aggressive growth and severe progression that would benefit from early intervention. By using a PCR-based screening approach, we first confirmed that previously known markers of hemangioma, namely FGF2 and GLUT1, are highly expressed in hemangioma. Nevertheless, these genes did not show any differential expression between severely progressing tumors and mild tumors. However, transcriptional upregulation of several Hedgehog signalling components, comprising the ligand Sonic Hedgehog (SHH), the transcription factor GLI2 and its target gene FOXA2 were detected in extremely aggressive hemangioma specimens during the proliferation phase. Notably, GLI2 was even overexpressed in involuting hemangiomas if they showed an aggressive growth pattern. In conclusion, our data suggest that overexpression of the Hedgehog components SHH, GLI2 and FOXA2 might be used as markers of an aggressive hemangioma that would benefit from too early intervention, while FGF2 and GLUT1 are more general markers of hemangiomas.

Molecular and immunohistochemical expression of apoptotic proteins Bax, Bcl-2 and Caspase 3 in infantile hemangioma tissues as an effect of propranolol treatment

BACKGROUND

Infantile hemangiomas (IHs) are the most common benign tumors of childhood. They are characterized by a unique clinical course with two phases, proliferation and involution, which are followed by regression. The therapy of infantile hemangiomas was revolutionized in 2008 by the introduction of propranolol, however, the mechanism of its influence on hemangiomas remains unclear.

METHODS

The study included 71 patients with IHs, 27 of whom were treated with propranolol while the remaining 44 were used as a comparative group. The expression of Bcl-2, Bax and Caspase3 was determined with immunohistochemistry and mRNA of Bax, Bcl-2 and Caspase3 were assessed with the use of RT-PCR.

RESULTS

Both methods revealed a statistically significant decrease in Bcl-2 expression and an increase in Bax in IHs tissues after propranolol treatment.

CONCLUSIONS

The results obtained for Bax and Bcl-2 proteins may indicate a link between the effect of propranolol and apoptosis. Higher Bax and lower Bcl-2 expression in the propranolol treated group indicates a strong pro- apoptotic action countering any anti-apoptotic activity; apoptosis was indicted in IH tissue as a potential result of propranolol treatment, with potential clinical impact in other tumors.

Fell-Muir Lecture: Regulatory mechanisms of skeletal and connective tissue development and homeostasis - lessons from studies of human disorders

Studies of proliferative hemangiomas have led to the discovery that interactions of endothelial cells with extracellular matrix and/or Vascular Endothelial Growth Factor (VEGF)-A stimulate the expression of VEGFR1, the VEGF decoy receptor, and suppress VEGF-dependent VEGFR2 signalling by a mechanism that requires the matrix-binding receptor Anthrax Toxin Receptor (ANTXR)1, VEGFR2, β1 integrin and the Nuclear Factor of Activated T cells (NFAT). In hemangioma endothelial cells, all these components are present, but are functionally compromised, so that the levels of VEGFR1 are extremely low and VEGFR2 signalling is constitutively active. Consequently, the levels of Hypoxia Inducible Factor (HIF)-1α and its transcriptional targets, VEGF-A and C-X-C motif chemokine 12 (CxCl12), are elevated and a positive VEGF-A feedback loop is established. Overexpression of ANTXR1, carrying a heterozygous Ala-to-Thr mutation, induces hemangioma-like signalling in control endothelial cells; VEGF signalling is normalized when wild-type ANTXR1 is overexpressed in hemangioma cells. These findings suggest that ANTXR1 functions as a negative regulator of VEGF-A signalling. Studies of a mouse model of the Growth Retardation, Alopecia, Pseudo-anodontia and Optic Atrophy (GAPO) syndrome, caused by the loss-of-function mutations in ANTXR1, as well as knock-in mice carrying the Ala-to-Thr ANTXR1 mutation, confirm that ANTXR1 functions as a suppressor of VEGF-A signalling. Cutaneous endothelial cells isolated from ANTXR1-deficient mice exhibit low levels of VEGFR1, elevated levels of VEGF-A, HIF-1α and CxCl12 and activated VEGFR2 signalling as in hemangioma. Increased numbers of myeloid cells in the skin of ANTXR1-deficient mice are associated with reduced vascularity and increased skin fibrosis, suggesting a mechanism for hemangioma involution and replacement by fibrotic scars. Through controlling VEGF-A signalling and extracellular matrix synthesis, ANTXR1 is emerging as a key regulator of skeletal and connective tissue development and homeostasis.

Surgical Treatment of Facial Infantile Hemangiomas: An Analysis Based on Tumor Characteristics and Outcomes

BACKGROUND

Surgical treatment of infantile hemangiomas may interfere with patient appearance. The use of an algorithm is essential to select candidates. The objective of this study was to evaluate outcomes of surgical treatment based on tumor characteristics.

METHODS

Seventy-four patients were treated surgically between 1997 and 2010. Demographics, tumor characteristics, surgical approach, and outcomes were evaluated.

RESULTS

The female-to-male ratio was 5.7:1. Mean age and follow-up were 24 years and 33 months, respectively. Surgery was elective in 83.8 percent and emergent in 16.2 percent of patients. Most frequent locations were lips, nose, eyelids, and cheeks. Surgery was performed during the proliferative phase in 43 patients (58.1 percent), and growth-related deformity was the main indication. No significant association between sex and the presence of complications or treatment indication was observed. Patients who underwent emergency procedures were younger (p = 0.0031) and had a higher incidence of evolutional complications (p = 0.012). Also, they were more frequently operated on during the proliferative phase (p = 0.011). Favorable outcome of surgical treatment was observed in both simple and complex cases for facial contour, volume reduction, and need for reoperation. The best candidates for elective surgery were patients with localized eyelid, nasal, or lip hemangiomas, presenting growth-related deformities during the proliferative phase. For patients undergoing emergency procedures, the best candidates were nonresponders to pharmacologic therapy with segmental periorbital hemangiomas, treated by partial resection.

CONCLUSIONS

A profile of patients and their specific surgical approach was established. Satisfactory results could be achieved following the proposed algorithm.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Disruption and inactivation of the PP2A complex promotes the proliferation and angiogenesis of hemangioma endothelial cells through activating AKT and ERK

Hemangioma is a benign vascular neoplasm of unknown etiology. In this study, we generated an endothelial-specific PyMT gene-expressing transgenic mouse model that spontaneously develops hemangioma. Based on this transgenic model, a specific binding between PyMT and the core AC dimer of protein phosphatase 2A (PP2A) was verified in hemangioma vascular endothelial cells. The binding between PyMT and the PP2A AC dimer resulted in dissociation of the B subunit from the PP2A complex and inactivation of PP2A phosphatases, which in turn activated AKT and ERK signaling and promoted cell proliferation, migration and angiogenesis in vitro and tumorigenesis in vivo. Consistent with the in vitro findings, decreased PP2A phosphatase activity and disruption of the PP2A heterotrimeric complex were also observed in both primary transgene-positive TG(+) mouse hemangioma endothelial cells (TG(+) HEC cells) and human proliferating phase hemangioma endothelial (human HEC-P) cells, but not in transgene-negative TG(-) mouse normal vascular endothelial cells (TG(-) NEC cells) and human involuting phase hemangioma endothelial (human HEC-I) cells. Further, it was observed that in human hemangioma cells, endoglin could compete with the PP2A/A, C subunits for binding to the PP2A/B subunit, thereby resulting in dissociation of the B subunit from the PP2A complex. Treatment of Tie2/PyMT transgenic mice with the PP2A activator FTY720 significantly delayed the occurrence of hemangioma. Our data provide evidence of a previously unreported anti-proliferation and anti-angiogenesis effect of PP2A in vascular endothelial cells, and show the therapeutic value of PP2A activators in hemangioma.

VEGFR-2 conformational switch in response to ligand binding

VEGFR-2 is the primary regulator of angiogenesis, the development of new blood vessels from pre-existing ones. VEGFR-2 has been hypothesized to be monomeric in the absence of bound ligand, and to undergo dimerization and activation only upon ligand binding. Using quantitative FRET and biochemical analysis, we show that VEGFR-2 forms dimers also in the absence of ligand when expressed at physiological levels, and that these dimers are phosphorylated. Ligand binding leads to a change in the TM domain conformation, resulting in increased kinase domain phosphorylation. Inter-receptor contacts within the extracellular and TM domains are critical for the establishment of the unliganded dimer structure, and for the transition to the ligand-bound active conformation. We further show that the pathogenic C482R VEGFR-2 mutant, linked to infantile hemangioma, promotes ligand-independent signaling by mimicking the structure of the ligand-bound wild-type VEGFR-2 dimer.

The effectiveness of propranolol in treating infantile haemangiomas: a meta-analysis including 35 studies

AIMS

Propranolol may have shown excellent results as a first line therapy in infantile haemangiomas (IHs) at all sites in the body, but this conclusion remains controversial. In an attempt to resolve this issue, we performed a meta-analysis.

METHODS

A search of the literature using PubMed, MEDLINE, Cochrane Library databases and China National Knowledge Infrastructure (CNKI) was performed to identify studies which estimated the efficacy of propranolol therapy in infants with haemangiomas all sites of the body. The pooled odds ratio (OR) along with the corresponding 95% confidence intervals (CI) were assessed using a fixed effects model.

RESULTS

Thirty-five studies involving 324 infantile haemangioma(IH) patients and 248 controls were retrieved and analyzed. The efficacy of propranolol was greater than other therapies in treating IHs (OR = 9.67, 95% CI 6.62, 14.12, P < 0.001). In a stratified analysis by sites of tumour, propranolol was a more effective therapy when compared with steroids (OR = 9.67, 95% CI 6.61, 14.15, P < 0.001), vincristine (OR = 9.00, 95% CI 2.15, 37.66, P = 0.003) and laser treatment (OR = 9.00, 95% CI 1.42, 57.12, P = 0.020) in treating cutaneous IHs (OR = 24.95, 95% CI 9.48, 65.64, P < 0.001), peri-ocular IHs (OR = 9.39, 95% CI 3.88, 22.71, P < 0.001), infantile airway haemangiomas (OR = 20.91, 95% CI 7.81, 55.96, P < 0.001) and infantile hepatic haemangiomas (OR = 9.89, 95% CI 1.20, 81.54, P = 0.033).

CONCLUSION

The current meta-analysis provided strong evidence for propranolol as a first line therapy for IHs.

Comparative Analysis of the Extracellular Matrix Composition in Proliferating and Involuted Infantile Hemangiomas

Background

Changes in the composition of the extracellular matrix (ECM) occur between the proliferating and involuted phases of infantile hemangiomas (IH), and are associated with angiogenic growth. We examined the composition of the ECM in proliferating and involuted IHs and assessed correlations between the composition of the ECM and whether the IH was in the proliferating or the involuted phase.

Methods

We evaluated IH samples from a cohort of patients who had five proliferating IHs and five involuted IHs. The following ECM molecules were analyzed using enzyme-linked immunosorbent assays and immunohistochemistry: laminin, fibronectin, collagen type I, collagen type II, and collagen type III.

Results

The involuted IHs had higher levels of deposition of collagen type III than the proliferating IHs. The median values (interquartile ranges) were 1.135 (0.946-1.486) and 1.008 (0.780-1.166) (P=0.019), respectively. The level of laminin was higher in involuted IHs than in proliferating IHs, with median values (interquartile ranges) of 3.191 (2.945-3.191) and 2.479 (1.699-3.284) (P=0.047), respectively. Abundant collagen type III staining was found in involuted IHs. Laminin α4 chain staining was clearly present within the basement membrane adjacent to the blood vessels, and was significantly more intense in involuted IHs than in proliferative IHs.

Conclusions

Involuted hemangiomas showed extensive deposition of collagen III and laminin, suggesting that differences in the composition of the ECM reflect stages of the development of IHs. This pattern may be due to the rapid senescence of IHs.

Management of Intraosseous Vascular Malformations of the Jaws in Children and Adolescents: Report of 6 Cases and Literature Review

Background

Intraosseous vascular malformations represent a rare clinical entity of the facial skeleton. The purpose of the current study was to present our experience in a Greek paediatric population and propose guidelines for the treatment of these jaws anomalies in children and adolescents.

Methods

A retrospective study (from 2009 to 2014) was performed to investigate the features and management of the intraosseous vascular anomalies in a Greek paediatric population.

Results

Six patients aged between 6 and 14 years were treated for intraosseous vascular malformations (4 venous and 2 arteriovenous) of the jaws. Five lesions were located in the mandible and one in the maxilla. In four lesions with pronounced vascularity superselective angiography, followed by embolization was performed. Individualized surgical treatment, depending on the size and vascularity of the lesions was applied in 4 patients.

Conclusions

The intraosseous vascular malformations of the jaws may escape diagnosis in paediatric patients. A multidisciplinary approach is important for their safe and efficient treatment. Embolization is recommended for extended high-flow lesions, either preoperatively or as a first-line treatment, when surgery is not feasible without significant morbidity.

Importance of GLUT1 in differential diagnosis of vascular anomalies

Vascular anomalies (VAs) include a group of distinct lesions, such as vascular system congenital malformations, as well as benign and malignant vascular tumors. These lesions may present similar clinical and histopathological features, leading to mistaken diagnoses and incorrect treatment choices. It is important that professionals responsible for monitoring the development of VAs conduct precise investigations and use the appropriate terminology. The human glucose transporter protein isoform 1 (GLUT1) has been proposed as a tool to aid in differential diagnosis between different VAs, given that it is a sensitive and specific marker for identification of infantile hemangiomas (HIs) in any organ. This article presents a review of the literature on this protein as an effective tool for identification and possible differential diagnosis between several VAs.

Prospective study of infantile haemangiomas: incidence, clinical characteristics and association with placental anomalies

BACKGROUND

The aetiology and exact incidence of infantile haemangiomas (IHs) are unknown. Prior studies have noted immunohistochemical and biological characteristics shared by IHs and placental tissue.

OBJECTIVES

We investigated the possible association between placental anomalies and the development of IHs, as well as the demographic characteristics and other risk factors for IHs.

PATIENTS AND METHODS

Pregnant women (n = 578) were prospectively enrolled and their offspring followed for 9 months. Placental evaluations were performed and demographic data collected on all mother-infant pairs.

RESULTS

We evaluated 594 infants: 34 haemangiomas [either IH or congenital (CH)] were identified in 29 infants, yielding an incidence of 4·5% for IH (27 infants) and 0·3% for CH (two infants). Placental anomalies were noted in almost 35% of haemangioma-related pregnancies, approximately twice the incidence noted in pregnancies with unaffected infants (P = 0·025). Other risk factors for IH included prematurity (P = 0·016) and low birth weight (P = 0·028). All IHs were present by 3 months of age, and cessation of growth had occurred in all by 9 months of age. Most occurred on the trunk. Of note, 20% of identified IHs were abortive or telangiectatic in nature, small focal lesions that did not proliferate beyond 3 months of age. Only one IH required intervention.

CONCLUSIONS

This is the first prospective American study to document the incidence of IHs in infants followed from birth to early infancy. The association with placental anomalies was statistically significant. The overall incidence mirrors prior estimates, but the need for treatment was lower than previously reported.

Educational paper: therapy of infantile haemangioma--history and current state (part II)

Infantile haemangioma (IH) is the most frequent tumour of infancy. Although it is benign and self-limiting, severe complications can arise due to localisation and fast tumour growth. Also, IHs leave scars after regression in more than half of the cases. Management and therapy of IH have changed greatly after 2008. This update provides an overview of the older therapy options before 2008, which mainly consisted of the administration of corticosteroids, and discusses the modern management with new therapy options such as β-blockers (both systemically and topically).

CONCLUSION

β-blockers are promising and are currently preferred above corticosteroids, but β-blockers still do not give a definitive treatment.

Educational paper: Pathogenesis of infantile haemangioma, an update 2014 (part I)

Infantile haemangioma (IH) is the most frequent childhood tumour. Although it is benign and self-limiting, severe complications can arise due to localisation and fast tumour growth. Management and therapy of IH has changed greatly after 2008 with propranolol. However, the pathogenesis remains elusive. This update provides an overview of all possible mechanisms currently considered. We discuss the possibility that several mechanisms act together, although local hypoxia seems to be important. Clinically, in about half of the cases, an IH is preceded by an anaemic macula (local ischaemia) or a so-called precursor lesion. Laboratory findings indicate stabilisation and an increased transcription activity of hypoxia-inducible factor 1 alpha (HIF1α), leading to up-regulation of its downstream target genes (such as vascular endothelial growth factor (VEGF)), which normally occurs in cases of hypoxia.

CONCLUSION

Three main hypotheses have been proposed, namely (1) the theory of tissue hypoxia, (2) the theory of embolization of placental endothelial cells and (3) the theory of increased angiogenic and vasculogenic activity.

Support for the hypoxia theory in the pathogenesis of infantile haemangioma

BACKGROUND

The pathogenesis of infantile haemangioma (IH) is unknown. Several mechanisms have been proposed, including hypoxia, which triggers upregulation and stabilization of hypoxia-inducible factor (HIF)1α. HIF1α stimulates downstream transcription of target genes that enhance angiogenesis.

AIM

To identify possible involvement of hypoxia in the pathogenesis of IH, as hypoxia signalling constitutes a potential therapeutic target.

METHODS

IH tissue samples collected during the period 1991-2011 (preserved in paraffin wax) were immunohistochemically analysed for HIF1α and the known HIF1α targets: BCL2/adenovirus E1B kD-interacting protein family member 3 (BNIP3), carbon anhydrase (CA)-IX, glucose transporter (GLUT)-1, phosphorylated protein kinase B (pAKT), phosphorylated S6 protein (pS6) and vascular endothelial growth factor (VEGF). Four observers independently assessed the findings.

RESULTS

Of the 10 IH samples, 2 appeared to be in the growth phase. In all samples, GLUT-1, BNIP3, pAKT and VEGF were positive, CA-IX was weakly positive, and HIF1α was negative. pS6 was positive in 9/10 cases and negative in 1/10.

CONCLUSIONS

Several factors implicated in hypoxia-induced angiogenesis may be involved in IH development. However, the small sample size and retrospective approach of the study preclude definitive conclusions. Prospective studies are needed to conclusively determine which of the factors involved in the (hypoxia) cascade are required for an IH to grow, and could thus be a possible target of drugs for IH treatment.

Propranolol in treatment of huge and complicated infantile hemangiomas in egyptian children

Background. Infantile hemangiomas (IHs) are the most common benign tumours of infancy. Propranolol has recently been reported to be a highly effective treatment for IHs. This study aimed to evaluate the efficacy and side effects of propranolol for treatment of complicated cases of IHs. Patients and Methods. This prospective clinical study included 30 children with huge or complicated IHs; their ages ranged from 2 months to 1 year. They were treated by oral propranolol. Treatment outcomes were clinically evaluated. Results. Superficial cutaneous hemangiomas began to respond to propranolol therapy within one to two weeks after the onset of treatment. The mean treatment period that was needed for the occurrence of complete resolution was 9.4 months. Treatment with propranolol was well tolerated and had few side effects. No rebound growth of the tumors was noted when propranolol dosing stopped except in one case. Conclusion. Propranolol is a promising treatment for IHs without obvious side effects. However, further studies with longer follow-up periods are needed.

Late rebound of infantile hemangioma after cessation of oral propranolol

Propranolol has become the first line of treatment for infantile hemangiomas (IHs), with a high response rate, but rebound growth after cessation of propranolol has been reported, primarily in the first year of life. We sought to determine the frequency and associated factors leading to late regrowth after successful treatment at an age when the proliferative phase has usually ceased. We retrospectively reviewed the clinical charts, serial photographs, and radiologic images of children with rebound IH occurring after the age of 15 months after a successful course of oral propranolol averaging 2.6 mg/kg/day (range 2-3 mg/kg/day). Thirteen (10 female, 3 male) of 212 patients (6%) treated with oral propranolol since 2008 were evaluated. The mean age at the start of treatment was 5.3 months (range 1.8-13 months), and an average of 10.3 months (range 4.5-16 months) of treatment was given. It took an average of 5.3 months (range 1-13.8 months) for a significant rebound to appear. Late rebound after successful propranolol indicates a prolonged proliferation phase of IH even after 15 months of age. This is compared with previous reports of rebound, which occurred primarily in infants younger than 1 year old. Late proliferation can occur in localized, small, mixed, and deep IH, even after several months of a positive response to propranolol. A second course of propranolol readily controlled the recurrence.

Study of the etiopathogenesis and differential diagnosis of oral vascular lesions by immunoexpression of GLUT-1 and HIF-1α

BACKGROUND

To investigate whether the immunohistochemical expression of GLUT-1 and HIF-1α is related to the diagnosis and pathogenesis of oral vascular lesions.

STUDY METHODS

Thirty cases each of pyogenic granuloma (PG) and hemangioma were studied. Antibodies against GLUT-1 and HIF-1α were detected by immunoperoxidase staining in 3-μm histological sections, and the results were analyzed qualitatively and quantitatively, respectively. Positive and negative cells were counted, and the mean number of positive cells was calculated for each case.

RESULTS

The initial diagnosis of hemangioma was maintained in only 7 (23%) of the 30 cases studied, which were positive for GLUT-1. The remaining 23 cases were reclassified as vascular malformation (VM) (n = 13) and PG (n = 10) due to the absence of staining. The endothelium of blood vessels was negative for GLUT-1 in all cases initially diagnosed as PG (n = 30). The percentage of HIF-1α-positive cells was higher in cases of PG, followed by hemangiomas and VMs (P = 0.005).

CONCLUSIONS

Histological features are not sufficient to establish the correct diagnosis of oral hemangiomas, and an accurate anamnesis is essential in these cases. In addition, these findings demonstrate that vascular lesions express mediators of angiogenesis, HIF-1α, and suggest that his process may play a role in the pathogenesis of vascular.

Infantile hemangiomas and retinopathy of prematurity: clues to the regulation of vasculogenesis

Retinopathy of prematurity (ROP) and infantile hemangiomas are vascular disorders that may share common mechanisms. This study examined a potential clinical association between these disorders in populations of preterm infants at two hospitals in the USA and Hungary. Clinically collected data from infants with gestational ages less than 32 weeks born between May 1, 2007 and December 31, 2010 seen in the University of Iowa Children's Hospital or the Department of Obstetrics and Gynecology, University of Pécs, were abstracted from electronic medical records and entered into a study database. Demographic and clinical variables were examined as potential covariates to the disorders of interest. Data were initially analyzed by center and then combined through meta-analysis. Six hundred eighty-four subjects were studied: 236 from Pécs and 448 from Iowa. There were no significant demographic differences between populations. Univariate analysis on each study population yielded covariates to ROP in each population, including infantile hemangioma, which were entered into a logistic regression model. These models were combined through random-effects meta-analysis and demonstrated a significant relationship between infantile hemangioma and ROP (odds ratio = 1.84, 95 % confidence interval 1.08-3.12).

CONCLUSION

Infantile hemangioma and ROP co-occur in premature infant populations. Further studies are needed to investigate the pathogenesis of both disorders.

Multimodality imaging of vascular anomalies

Vascular malformations and hemangiomas are common in children but remain a source of confusion during diagnosis, in part because of the lack of a uniform terminology. With the existing treatments for hemangiomas and vascular malformations, it is important to make the correct diagnosis initially to prevent adverse physical and emotional sequelae in not only the child but also the family. The diagnosis of vascular malformations is made primarily by the clinician and based on the physical exam. Imaging is carried out using predominantly ultrasound (US) and magnetic resonance imaging (MRI), which are complementary modalities. In most cases of vascular anomalies, US is the first line of imaging as it is readily available, less expensive, lacks ionizing radiation and does not require sedation. MRI is also of great help for further characterizing the lesions. Conventional arteriography is reserved for cases that require therapeutic intervention, more commonly for arteriovenous malformations. Radiographs usually play no role in diagnosing vascular anomalies in children. In this article, the author describes the terminology and types of hemangiomas and vascular malformations and their clinical, histological features, as well as the imaging approach and appearance.

Propranolol in the treatment of problematic infantile hemangioma: review of 35 consecutive patients from a vascular anomalies clinic

BACKGROUND

Propranolol, a nonselective β-blocker, has been reported as efficient for controlling the growth of complicated infantile hemangiomas (IHs). No uniformly accepted protocol exists regarding the administration of oral propranolol for IH.

OBJECTIVE

We sought to share our experience using propranolol for problematic IH and to evaluate the efficacy of this treatment modality.

METHODS

A retrospective chart review analysis was performed for 35 consecutive children treated with propranolol as an oral solution on an outpatient basis in our dermatology/vascular anomalies clinic. A protocol was established with the help of our pediatric cardiologists, including pretreatment electrocardiography and echocardiography. Medical photographs taken after 2 months of treatment were rated by two independent evaluators.

RESULTS

We treated 31 girls and 4 boys with a median age of 3.5 months. Rapid improvement was reported in the first days of treatment in 34 patients. Mean improvement after 2 months was 61.5%. No serious adverse effects were reported.

CONCLUSION

Propranolol was effective in controlling the proliferative phase of problematic IH. It was well tolerated in our study. Outpatient treatment is possible if parents follow strict guidelines. Propranolol should be a first-line treatment for problematic IH in carefully selected patients.

Surgical management of head and neck vascular anomalies in children: a retrospective analysis of 42 patients

OBJECTIVE

This article aimed to present a series of surgically treated head and neck vascular anomalies during a 12-year period, highlighting the epidemiology, diagnostic approach, indications for surgery, and final clinical outcome.

STUDY DESIGN

The medical records of all patients with head and neck vascular anomalies, surgically treated at our department from 1998 to 2010, were reviewed retrospectively.

RESULTS

A total of 42 patients with 46 vascular anomalies were identified. Patients' diagnoses included vascular tumors, hemangiomas mainly (18 cases), and various vascular malformations (26 cases). All patients were submitted to surgical treatment (excision-resection) to resolve main clinical symptoms (ulceration, bleeding, impaired mastication and feeding, airway obstruction) and/or esthetic issues. Recurrence was noted in 3 patients.

CONCLUSION

Accurate differential diagnosis based on history, physical examination, and imaging, is the key to optimal treatment. Surgical intervention is warranted for small to moderately extended lesions to avoid complications and/or esthetic concerns and psychosocial distress.