Hypoxia-induced mediators of stem/progenitor cell trafficking are increased in children with hemangioma

Infantile hemangioma: the common and enigmatic vascular tumor

Infantile hemangioma (IH) is a benign vascular tumor that occurs in 5% of newborns. The tumor follows a life cycle of rapid proliferation in infancy, followed by slow involution in childhood. This unique life cycle has attracted the interest of basic and clinical scientists alike as a paradigm for vasculogenesis, angiogenesis, and vascular regression. Unanswered questions persist about the genetic and molecular drivers of the proliferating and involuting phases. The beta blocker propranolol usually accelerates regression of problematic IHs, yet its mechanism of action on vascular proliferation and differentiation is unclear. Some IHs fail to respond to beta blockers and regrow after discontinuation. Side effects occur and long-term sequelae of propranolol treatment are unknown. This poses clinical challenges and raises novel questions about the mechanisms of vascular overgrowth in IH.

Apolipoprotein A-I Binding Protein Inhibits the Formation of Infantile Hemangioma through Cholesterol-Regulated Hypoxia-Inducible Factor 1α Activation

Infantile hemangioma (IH) is the most frequent vascular tumor of infancy with unclear pathogenesis; disordered angiogenesis is considered to be involved in its formation. Apolipoprotein A-I binding protein (AIBP)-also known as NAXE (NAD [P]HX epimerase)-a regulator of cholesterol metabolism, plays a critical role in the pathological angiogenesis of mammals. In this study, we found that AIBP had much lower expression levels in both tissues from patients with IH and hemangioma endothelial cells (HemECs) than in adjacent normal tissues and human dermal vascular endothelial cells, respectively. Knockout of NAXE by CRISPR-Cas9 in HemECs enhanced tube formation and migration, and NAXE overexpression impaired tube formation and migration of HemECs. Interestingly, AIBP suppressed the proliferation of HemECs in hypoxia. We then found that reduced expression of AIBP correlated with increased hypoxia-inducible factor 1α levels in tissues from patients with IH and HemECs. Further mechanistic investigation demonstrated that AIBP disrupted hypoxia-inducible factor 1α signaling through cholesterol metabolism under hypoxia. Notably, AIBP significantly inhibited the development of IH in immunodeficient mice. Furthermore, using the validated mouse endothelial cell (ie, EOMA cells) and Naxe-/- mouse models, we demonstrated that both endogenous AIBP from tumors and AIBP in the tumor microenvironment limit the formation of hemangioma. These findings suggested that AIBP was a player in the pathogenesis of IH and could be a potential pharmacological target for treating IH.

KLF2 Orchestrates Pathological Progression of Infantile Hemangioma through Hemangioma Stem Cell Fate Decisions

Infantile hemangioma (IH) is the most prevalent vascular tumor during infancy, characterized by a rapid proliferation phase of disorganized blood vessels and spontaneous involution. IH possibly arises from a special type of multipotent stem cells called hemangioma stem cells (HemSCs), which could differentiate into endothelial cells, pericytes, and adipocytes. However, the underlying mechanisms that regulate the cell fate determination of HemSCs remain elusive. In this study, we unveil KLF2 as a candidate transcription factor involved in the control of HemSCs differentiation. KLF2 exhibits high expression in endothelial cells in proliferating IH but diminishes in adipocytes in involuting IH. Using a combination of in vitro culture of patient-derived HemSCs and HemSCs implantation mouse models, we show that KLF2 governs the proliferation, apoptosis, and cell cycle progression of HemSCs. Importantly, KLF2 acts as a crucial determinant of HemSC fate, directing their differentiation toward endothelial cells while inhibiting adipogenesis. Knockdown of KLF2 induces a proadipogenic transcriptome in HemSCs, leading to impaired blood vessel formation and accelerated adipocyte differentiation. Collectively, our findings highlight KLF2 as a critical regulator controlling the progression and involution of IH by modulating HemSC fate decisions.

Propranolol: a new pharmacologic approach to counter retinopathy of prematurity progression

Despite the evident progress in neonatal medicine, retinopathy of prematurity (ROP) remains a serious threat to the vision of premature infants, due to a still partial understanding of the mechanisms underlying the development of this disease and the lack of drugs capable of arresting its progression. Although ROP is a multifactorial disease, retinal vascularization is strictly dependent on oxygen concentration. The exposition of the retina of a preterm newborn, still incompletely vascularized, to an atmosphere relatively hyperoxic, as the extrauterine environment, induces the downregulation of proangiogenic factors and therefore the interruption of vascularization (first ischemic phase of ROP). However, over the following weeks, the growing metabolic requirement of this ischemic retina produces a progressive hypoxia that specularly promotes the surge of proangiogenic factors, finally leading to proliferative retinopathy (second proliferative phase of ROP). The demonstration that the noradrenergic system is actively involved in the coupling between hypoxia and the induction of vasculogenesis paved the way for a pharmacologic intervention aimed at counteracting the interaction of noradrenaline with specific receptors and consequently the progression of ROP. A similar trend has been observed in infantile hemangiomas, the most common vascular lesion of childhood induced by pre-existing hypoxia, which shares similar characteristics with ROP. The fact that propranolol, an unselective antagonist of β1/2 adrenoceptors, counteracts the growth of infantile hemangiomas, suggested the idea of testing the efficacy of propranolol in infants with ROP. From preclinical studies, ongoing clinical trials demonstrated that topical administration of propranolol likely represents the optimal approach to reconcile its efficacy and maximum safety. Given the strict relationship between vessels and neurons, recovering retinal vascularization with propranolol may add further efficacy to prevent retinal dysfunction. In conclusion, the strategy of contrasting precociously the progression of the disease appears to be more advantageous than the current wait-and-see therapeutic approach, which instead is mainly focused on avoiding retinal detachment.

Global research trends of infantile hemangioma: A bibliometric and visualization analysis from 2000 to 2022

Background

Infantile hemangioma (IH) has received global attention, resulting in a significant volume of literature. However, there is a lack of bibliometric analyses specifically focusing on IH publications. This study aims to fill this gap by conducting a comprehensive analysis of IH publications, investigating their characteristics, contribution distribution, and developmental trends. By enhancing our understanding of IH and identifying potential research topics and collaborators, this study will contribute to the advancement of the field.

Methods

A total of 4333 articles and reviews on IH were collected from the Web of Science (WoS) database, spanning the years 2000-2022. The study encompassed a comprehensive analysis of IH publications, evaluating their quantity and quality. Additionally, we profiled publishing groups based on country, institution, author publication records, and collaboration networks. Lastly, we identified and summarized the prominent research topics.

Results

Annual publications on IH have increased over the past 20 years. The United States has the highest number of publications and the highest total number of citations. Pediatric Dermatology was the most influential journal in the IH field. The citation analysis indicated that the articles published by Léauté-Labrèze in 2008 had the highest number of citations. The articles published by North PE in 2000 and Boye E in 2001 laid a certain research foundation for this field. Concerning institutions, most of the cooperative relationships were established in the same country/region. The United States has the largest number of scientific research institutions and IH researchers, leading most of the cross-country collaboration. The University of California, San Francisco, Medical College of Wisconsin, Harvard University, and Shanghai Jiaotong University were the research centers that published the most IH-related research. Frieden IJ, Mulliken JB, and Drolet BA were the top three most influential authors. Frieden IJ, Garzon MC, and Mulliken JB were the top three authors with the most cited frequency. In addition, keywords and keyword co-occurrence networks prompted that the pathological mechanism of IH, clinical analysis, and other vascular anomalies are research hotspots. Analysis of trending topics suggests that research on IH has evolved from treatment-focused studies towards investigations of other vascular diseases and a series of clinical case studies. Currently, clinical case studies receive the most attention in the field.

Conclusions

This comprehensive bibliometric study provides a thorough analysis of post-2000 publications in the field of IH, offering insights into current research trends for the first time. The findings suggest that future investigations will continue to prioritize understanding IH mechanisms, treatment approaches, and treatment evaluation. Furthermore, the exploration of other vascular diseases and the inclusion of clinical case studies are expected to contribute to advancements in IH clinical practice. By identifying potential collaborators, partner institutions, and new research avenues, this study offers valuable guidance for future in-depth research on IH.

Platelet functional abnormalities in pediatric patients with kaposiform hemangioendothelioma/Kasabach-Merritt phenomenon

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of infancy that is commonly associated with a life-threatening thrombocytopenic condition, Kasabach-Merritt phenomenon (KMP). Platelet CLEC-2, tumor podoplanin interaction is considered the key mechanism of platelet clearance in these patients. Here, we aimed to assess platelet functionality in such patients. Three groups of 6 to 9 children were enrolled: group A with KHE/KMP without hematologic response (HR) to therapy; group B with KHE/KMP with HR; and group C with healthy children. Platelet functionality was assessed by continuous and end point flow cytometry, low-angle light scattering analysis (LaSca), fluorescent microscopy of blood smears, and ex vivo thrombi formation. Platelet integrin activation in response to a combination of CRP (GPVI agonist) and TRAP-6 (PAR1 agonist), as well as calcium mobilization and integrin activation in response to CRP or rhodocytin (CLEC-2 agonist) alone, were significantly diminished in groups A and B. At the same time, platelet responses to ADP with or without TRAP-6 were unaltered. Thrombi formation from collagen in parallel plate flow chambers was also noticeably decreased in groups A and B. In silico analysis of these results predicted diminished amounts of CLEC-2 on the platelet surface of patients, which was further confirmed by immunofluorescence microscopy and flow cytometry. In addition, we also noted a decrease in GPVI levels on platelets from group A. In KHE/KMP, platelet responses induced by CLEC-2 or GPVI activation are impaired because of the diminished number of receptors on the platelet surface. This impairment correlates with the severity of the disease and resolves as the patient recovers.

Apelin Receptor Can Act as a Specific Marker and Promising Therapeutic Target for Infantile Hemangioma

Infantile hemangioma (IH), the most common benign tumor in infancy, is generally sensitive to propranolol treatment. However, the challenge remains because resistance or recurrence could occur in some patients, and the mechanism or target of propranolol remains unknown. Therefore, advancement in the drug development is needed. In this study, we explored whether apelin receptor (APJ) can become a candidate target. We found that APJ is expressed only in endothelial cells of IH (HemECs) but not in other vascular anomalies, and its antagonist, ML221, can negatively regulate cellular viability and functions of HemECs. This inhibitory effect could be replicated in a murine hemangioma model. Importantly, in vitro experiments also indicated that ML221 failed to affect the proliferation or angiogenesis of normal endothelial cells or APJ-knockout HemECs. Through analysis of the phosphoantibody microarray data, ML221 was revealed to have an inhibitory effect on HemECs by suppressing the activation of mitogen-activated protein kinase/extracellular signal-regulated kinase pathway. These results verified the distinctive expression of APJ in IH and specific inhibition of HemEC activity caused by ML221. In addition, APJ was also detected in propranolol-resistant IH. Collectively, we propose that APJ can act as a specific marker and a promising therapeutic target for IH, which will facilitate further drug development.

Molecular Mechanisms of Carcinogenesis in Pediatric Airways Tumors

Primary tumors of the airways in the pediatric population are very rare entities. For this reason, little is known about the pathogenesis of these neoplasms. Understanding the biology has different practical implications: for example, it could help in the differential diagnosis, have a prognostic significance, or may lead to the development of a targeted therapy. The aim of this article is to present the current knowledge about pediatric airways tumors, focusing on the molecular mechanisms that cause the onset and progression of these neoplasms. After a brief introduction of epidemiology and clinical presentation, the tumorigenesis of the most frequent pediatric airways tumors will be described: Juvenile-onset recurrent respiratory papillomatosis (JORRP), Subglottic Hemangiona (SH), Rhabdomyosarcoma (RMS), and Mucoepidermoid carcinoma (MEC).

Three-Dimensional Microtumor Formation of Infantile Hemangioma-Derived Endothelial Cells for Mechanistic Exploration and Drug Screening

Infantile hemangioma (IH) is the most prevalent type of vascular tumor in infants. The pathophysiology of IH is unknown. The tissue structure and physiology of two-dimensional cell cultures differ greatly from those in vivo, and spontaneous regression often occurs during tumor formation in nude mice and has severely limited research into the pathogenesis and development of IH. By decellularizing porcine aorta, we attempted to obtain vascular-specific extracellular matrix as the bioink for fabricating micropattern arrays of varying diameters via microcontact printing. We then constructed IH-derived CD31+ hemangioma endothelial cell three-dimensional microtumor models. The vascular-specific and decellularized extracellular matrix was suitable for the growth of infantile hemangioma-derived endothelial cells. The KEGG signaling pathway analysis revealed enrichment primarily in stem cell pluripotency, RAS, and PI3KAkt compared to the two-dimensional cell model according to RNA sequencing. Propranolol, the first-line medication for IH, was also used to test the model's applicability. We also found that metformin had some impact on the condition. The three-dimensional microtumor models of CD31+ hemangioma endothelial cells were more robust and efficient experimental models for IH mechanistic exploration and drug screening.

Real-time optical imaging of the hypoxic status in hemangioma endothelial cells during propranolol therapy

Infantile hemangioma (IH) is the most common microvascular tumor of infancy involving the area of head and neck. One of the most important independent risk factors of IH is the hypoxia microenvironment. Fluorescent chemosensor provides a noninvasive intervention, high spatiotemporal resolution, ultrasensitive response, and real-time feedback approach to reveal the hypoxic status of cells. Our research group developed an ultrasensitive fluorescent chemosensor, HNT-NTR, and investigated the potential ability of imaging the hypoxic status of hemangioma-derived endothelial cells (HemECs). In this study, we successfully visualized the propranolol (PRN) treatment in HemECs using NHT-NTR with “Turn-off” sensing method. This chemosensor exhibited high sensitivity and selectivity for optical imaging of hypoxic status with fast responsiveness, real-time feedback and durable photostability of the fluorescent signal. It was also confirmed that HNT-NTR could monitor nitroreductase in vivo. Paramountly, we expected this chemosensor to offer an available optical method for imaging of the hypoxic status and visualizing the therapeutic status of PRN therapy in IH with the hypoxia-imaging capability.

Propranolol inhibits the angiogenic capacity of hemangioma endothelia via blocking β-adrenoceptor in mast cell

BACKGROUND

Propranolol, a non-selective blocker of the β-adrenoceptor (AR), is a first-line treatment for infantile hemangioma (IH). Mast cells have been implicated in the pathophysiology of propranolol-treated hemangioma. However, the function of mast cells remains unclear.

METHODS

HMC-1s (Human mast cell line) having been treated with propranolol for 24 h were centrifuged, washed with PBS twice, and maintained in cell culture medium for another 24 h. The supernatants with propranolol which were named as propranolol-treated HMC-1s supernatants were obtained. The expression of cytokines and mediators was examined among HMC-1s dealt with propranolol. HemECs (hemangioma endothelial cells) were co-cultured with propranolol-treated HMC-1s supernatants, and their proliferation and apoptosis were investigated. The autophagic-related protein was examined in HemECs using immunoblot.

RESULTS

In propranolol-treated HMC-1s, the expressions of ADRB1 (β1-AR) and ADRB2 (β2-AR) were reduced by 70% and 60%, respectively, and that of cytokines and mediators were reduced. The proliferation was decreased, but apoptosis and autophagy were induced in HemECs treated with propranolol-treated HMC-1s supernatants. However, propranolol can work well in shRNA-ADRB1 or shRNA-ADRB2 transfected HMC-1s.

CONCLUSIONS

Propranolol inhibit the proliferation of HemECs and promote their apoptosis and autophagy through acting on both β1 and β2 adrenoceptor in mast cell.

IMPACT

Treated with propranolol, β1, and β2 adrenoceptor on human mast cell expression was reduced significantly. After hemangioma endothelial cell treated with the supernatants from propranolol-treated human mast cell, its proliferation was decreased, but apoptosis and autophagy were significantly induced. Propranolol can work well in shRNA-ADRB1 or shRNA-ADRB2 transfected HMC-1s. Mast cells may have a role in the action of propranolol in infantile hemangioma through both β1 and β2 adrenoceptors to inhibit the angiogenic capacity of hemangioma endothelial cells.

Vascular endothelial growth factor response with propranolol therapy in patients with infantile hemangioma

Vascular endothelial growth factor-A (VEGF-A) is a master regulator of angiogenesis, with higher levels in infantile hemangioma (IH). The effects of propranolol on IH are not fully understood and may involve vasoconstriction, angiogenesis inhibition, and apoptosis induction. Therefore, we examined the effects of propranolol therapy on levels of VEGF-A in patients with IH in the proliferative phase and compared the VEGF-A levels to those in untreated patients in the involuting or involuted phases, as well as studied the consistency between the clinical and VEGF responses in patients receiving treatment. In a prospective study, we compared 24 patients with IH in the proliferative phase to 9 patients with IH in the involuting or involuted phase, assessing clinical responses to therapy and changes in VEGF-A levels after 3 months. The median VEGF level before treatment was 275 pg/ml; however, after 3 months, the level significantly decreased to 100 pg/ml (P = 0.007). Median VEGF was significantly higher in patients in the proliferative phase after 3 months of treatment (100 pg/ml) as compared to those in the involuting phase (50 pg/ml). We found no significant correlation between VEGF level and IH size reduction. Propranolol therapy induced a significant decline in VEGF levels at the 3-month evaluation in patients in the proliferative phase; however, this did not reach the levels of IH in the involuting phase. VEGF response was not translated to a clinical response in some patients with IH. These results put in uncertainty the clinical benefit of targeting VEGF pathway in IH.

Infantile hepatic hemangiomas: looking backwards and forwards

Infantile hepatic hemangiomas (IHHs) are common benign tumors seen in the liver of infants. IHHs are true infantile hemangiomas (IHs) and have phases of proliferation and involution parallel to those of cutaneous IHs. The definition and classification of IHH are still confusing in the literature. The mechanisms during the pathogenesis of IHH have yet to be discovered. The clinical manifestations of IHH are heterogeneous. Although most IHH lesions are asymptomatic, some lesions can lead to severe complications, such as hypothyroidism, consumptive coagulopathy, and high-output congestive cardiac failure. Consequently, some patients can possibly encounter a fatal clinical condition. The heterogeneity of the lesions and the occurrence of disease-related comorbidities can make the treatment of IHH challenging. Oral propranolol is emerging as an effective systemic approach to IHH with obvious responses in tumor remission and symptom regression. However, the precise clinical characteristics and treatment strategies for patients with severe IHH have not yet been well established. Here, we summarize the epidemiology, pathogenic mechanism, clinical manifestations, diagnosis, and treatment of IHH. Recent updates and future perspectives for IHH will also be elaborated.

Infantile hemangiomas β3-adrenoceptor overexpression is associated with nonresponse to propranolol

BACKGROUND

Propranolol (antagonist of β₁-/β₂-AR but minimally active against β₃-AR) is currently the first-line treatment for infantile hemangiomas (IH). Its efficacy is attributed to the blockade of β₂-AR. However, its success rate is ~60%. Considering the growing interest in the angiogenic role of β₃-ARs, we evaluated a possible relationship between β₃-AR expression and response to propranolol.

METHODS

Fifteen samples of surgical biopsies were collected from patients with IH. Three were taken precociously from infants and then successfully treated with propranolol (responder group). Twelve were taken later, from residual lesions noncompletely responsive to propranolol (nonresponder group). A morphometrical analysis of the percentage of β₁-, β₂-, and β₃-ARs positively stained area was compared between the two groups.

RESULTS

While no difference was found in both β₁- and β₂-AR expression level, a statistically significant increase of β₃-AR positively stained area was observed in the nonresponder group.

CONCLUSIONS

Although the number of biopsies is insufficient to draw definitive conclusions, and the different β-AR pattern may be theoretically explained by the different timing of samplings, this study suggests a possible correlation between β₃-AR expression and the reduced responsiveness to propranolol treatment. This study could pave the way for new therapeutic perspectives to manage IH.

IMPACT

Propranolol (unselective antagonist of β₁ and β₂-ARs) is currently the first-line treatment for IHs, with a success rate of ~60%. Its effectiveness has been attributed to its ability to block β₂-ARs. However, β₃-ARs (on which propranolol is minimally active) were significantly more expressed in hemangioma biopsies taken from patients nonresponsive to propranolol. This study suggests a possible role of β₃-ARs in hemangioma pathogenesis and a possible new therapeutic target.

β3-Adrenoceptor, a novel player in the round-trip from neonatal diseases to cancer: Suggestive clues from embryo

The role of the β-adrenoceptors (β-ARs) in hypoxia-driven diseases has gained visibility after the demonstration that propranolol promotes the regression of infantile hemangiomas and ameliorates the signs of retinopathy of prematurity (ROP). Besides the role of β2-ARs, preclinical studies in ROP have also revealed that β3-ARs are upregulated by hypoxia and that they are possibly involved in retinal angiogenesis. In a sort of figurative round trip, peculiarities typical of ROP, where hypoxia drives retinal neovascularization, have been then translated to cancer, a disease equally characterized by hypoxia-driven angiogenesis. In this step, investigating the role of β3-ARs has taken advantage of the assumption that cancer growth uses a set of strategies in common with embryo development. The possibility that hypoxic induction of β3-ARs may represent one of the mechanisms through which primarily embryo (and then cancer, as an astute imitator) adapts to grow in an otherwise hostile environment, has grown evidence. In both cancer and embryo, β3-ARs exert similar functions by exploiting a metabolic shift known as the Warburg effect, by acquiring resistance against xenobiotics, and by inducing a local immune tolerance. An additional potential role of β3-AR as a marker of stemness has been suggested by the finding that its antagonism induces cancer cell differentiation evoking that β3-ARs may help cancer to grow in a nonhospital environment, a strategy also exploited by embryos. From cancer, the round trip goes back to neonatal diseases for which new possible interpretative keys and potential pharmacological perspectives have been suggested.

Infantile Hemangiomas: An Update on Pathogenesis and Treatment

Infantile hemangiomas are the most common benign vascular tumors in infancy. This review includes an update on the current knowledge on pathogenesis, a discussion on indications for treatment, and a review of the mechanisms underlying the different treatment methods. Although most infantile hemangiomas require only active observation because of their natural course, which results in involution, about 10% present with complications that require immediate treatment. The basic treatment includes systemic and topical options. In cases of insufficient response or rebound growth, other forms of treatment should be considered. In some cases, combined therapy might be initiated.

Cellular heterogeneity and immune microenvironment revealed by single-cell transcriptome in venous malformation and cavernous venous malformation

Venous malformation (VM) and cavernous venous malformation (CVM) are two types of vascular malformations. Even if the two diseases are similar in appearance and imaging, the distinct cellular components and signaling pathways between them might help distinguish the two from a molecular perspective. Here, we performed single-cell profiling of 35,245 cells from two VM samples and three CVM samples, with a focus on endothelial cells (ECs), smooth muscle cells (SMCs) and immune microenvironment (IME). Clustering analysis based on differential gene expression unveiled 11 specific cell types, and determined CVM had more SMCs. Re-clustering of ECs and SMCs indicated CVM was dominated by arterial components, while VM is dominated by venous components. Gene set variation analysis suggested the activation of inflammation-related pathways in VM ECs, and upregulation of myogenesis pathway in CVM SMCs. In IME analysis, immune cells were identified to accounted for nearly 30% of the total cell number, including macrophages, monocytes, NK cells, T cells and B cells. Notably, more macrophages and monocytes were discovered in VM, indicating innate immune responses might be more closely related to VM pathogenesis. In addition, angiogenesis pathway was highlighted among the significant pathways of macrophages & monocytes between CVM and VM. In VM, VEGFA was highly expressed in macrophages & monocytes, while its receptors were all abundantly present in ECs. The close interaction of VEGFA on macrophages with its receptors on ECs was also predicted by CellPhoneDB analysis. Our results document cellular composition, significant pathways, and critical IME in CVM and VM development.

Infantile hemangioma. Part 1: Epidemiology, pathogenesis, clinical presentation and assessment

Infantile hemangioma (IH) is the most common pediatric vascular tumor. Its pathogenesis is poorly understood but thought to represent an aberrant response of pluripotent stem cells to stimuli such as hypoxia and the renin-angiotensin-system. IH usually appears during the first few weeks of life and follows a characteristic natural trajectory of proliferation and involution. Their clinical appearance depends on their depth and distribution. Classification comprises superficial, mixed and deep IH as well as IH with minimal or arrested growth. Multifocal IHs are more likely to be associated with infantile hepatic hemangioma, and although the need for screening based on a specific number of IH has been recently debated, 5 remains the most widely acceptable cut off point. Large facial or lumbar IH warrants investigation for PHACE and LUMBAR syndrome, respectively. Complications of IH include ulceration, obstruction or functional impairment, hypothyroidism, and cosmetic sequelae. Differential diagnoses mostly consist of other vascular tumors and vascular malformations, though IH may sometimes mimic non-vascular tumors or developmental anomalies. Diagnosis is usually clinical and biopsy rarely indicated. High-frequency ultrasonography may help with the differential diagnosis, particularly with subcutaneous lesions. Referral to other specialists may be required in specific cases.

Hypoxia-Induced Cyr61/CCN1 Production in Infantile Hemangioma

BACKGROUND

Hypoxia may play a role in the pathogenesis of infantile hemangioma. Cysteine-rich angiogenic inducer 61 (Cyr61), or CCN1, can be induced under hypoxic conditions in several types of cells. However, whether CCN1 has any impact on infantile hemangioma remains unknown. This study aims to explore the expression of CCN1 in infantile hemangioma and to investigate the effect of hypoxia on CCN1 and vascular endothelial growth factor-A (VEGF-A) production.

METHODS

Hemangioma-derived endothelial cells and hemangioma-derived stem cells were isolated from surgical specimens of proliferative infantile hemangioma. RNA extracted from infantile hemangioma tissue, hemangioma-derived endothelial cells, and hemangioma-derived stem cells was used to analyze gene expression by real-time polymerase chain reaction. The effects of CCN1 blockade were examined in hemangioma-derived stem cells. Immunostaining, immunoblotting, and enzyme-linked immunosorbent assays were used to assess protein expression.

RESULTS

By double-label immunofluorescence staining, the authors first identified that CCN1 was abundant in proliferative infantile hemangioma lesions and colocalized well with immature microvessels. The authors found that the mRNA level of CCN1 in proliferative infantile hemangioma was significantly higher than in healthy controls, as was involuting infantile hemangioma. Treatment with the hypoxia inducer cobalt chloride dramatically increased CCN1 production in hemangioma-derived endothelial cells in a time-dependent manner. Furthermore, blocking or knockdown of CCN1 expression reduced the expression of VEGF-A in hemangioma-derived stem cells. Lastly, the signaling pathway study showed that CCN1 up-regulation of VEGF-A synthesis in hemangioma-derived stem cells depends on nuclear factor-κB and JNK activation.

CONCLUSIONS

These findings provide new evidence that CCN1 participates in the crosstalk between hemangioma-derived endothelial cells and hemangioma-derived stem cells through promoting VEGF-A expression in the hypoxic environment of infantile hemangioma angiogenesis and vasculogenesis. Targeting of CCN1 might be a novel therapeutic strategy for infantile hemangioma.

Critical role of Aquaporin-1 and telocytes in infantile hemangioma response to propranolol beta blockade

Propranolol, a nonselective β-adrenergic receptor (ADRB) antagonist, is the first-line therapy for severe infantile hemangiomas (IH). Since the incidental discovery of propranolol efficacy in IH, preclinical and clinical investigations have shown evidence of adjuvant propranolol response in some malignant tumors. However, the mechanism for propranolol antitumor effect is still largely unknown, owing to the absence of a tumor model responsive to propranolol at nontoxic concentrations. Immunodeficient mice engrafted with different human tumor cell lines were treated with anti-VEGF bevacizumab to create a model sensitive to propranolol. Proteomics analysis was used to reveal propranolol-mediated protein alteration correlating with tumor growth inhibition, and Aquaporin-1 (AQP1), a water channel modulated in tumor cell migration and invasion, was identified. IH tissues and cells were then functionally investigated. Our functional protein association networks analysis and knockdown of ADRB2 and AQP1 indicated that propranolol treatment and AQP1 down-regulation trigger the same pathway, suggesting that AQP1 is a major driver of beta-blocker antitumor response. Examining AQP1 in human hemangioma samples, we found it exclusively in a perivascular layer, so far unrecognized in IH, made of telocytes (TCs). Functional in vitro studies showed that AQP1-positive TCs play a critical role in IH response to propranolol and that modulation of AQP1 in IH-TC by propranolol or shAQP1 decreases capillary-like tube formation in a Matrigel-based angiogenesis assay. We conclude that IH sensitivity to propranolol may rely, at least in part, on a cross talk between lesional vascular cells and stromal TCs.

Evaluation of plasma and urinary levels of vascular endothelial growth factor and matrix metalloproteinase-9 in patients with infantile hemangioma

BACKGROUND

The pathogenesis of infantile hemangioma (IH) is not fully understood. It has been suggested that angiogenic factors increase in the proliferative stage, decreasing subsequently in the regression phase.

OBJECTIVES

To evaluate vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP-9) levels, according to infantile hemangioma (IH) growth stages and size, and to compare these levels in patients with IH and control subjects.

METHODS

This cross-sectional study included 68 patients with IH and 25 control subjects. Plasma and urinary MMP-9 and VEGF levels were evaluated during proliferative and regression phases. These levels were correlated with tumor size measured by ultrasonography. Nonparametric tests were performed.

RESULTS

Among 68 patients with IH, 55 (81%) were female. Age ranged from 1 to 40 months (median 7.0 months). There was no difference in plasma and urinary levels of VEGF and MMP-9 between patients and control subjects. There were no significant differences in these levels between IH patients younger or older than 12 months of age, as a cutoff between proliferative and involution phases. No significant correlation was observed between tumor size and levels of the markers (R < 0.20 and P > 0.05 for all comparisons).

CONCLUSION

In our large sample, levels of VEGF and MMP-9 did not reflect the characteristic increased angiogenesis in patients with IH when compared to healthy subjects. In addition, these markers were not increased in the proliferative stage of the IH and did not correlate with tumor size.

Paediatrics: how to manage infantile haemangioma

Infantile haemangiomas (IHs) are relatively common benign vascular tumours found in the paediatric population. They have varying sizes and involve different depths in the skin leading to various colours, shapes and textures. Although considered harmless in most cases, they may lead to life-threatening complications or cause permanent disfigurations and organ dysfunction. For problematic IHs, the treatment options include oral and topical beta-blockers, systemic corticosteroids, laser treatment, and surgery. In this narrative review, the treatment options for problematic IH are compared and delivered concisely to facilitate the clinical decisions from practitioners, including those in primary care settings. Oral propranolol is currently considered the first-line intervention for problematic IHs. For superficial lesions, there is robust evidence for the use of topical timolol maleate. Systemic corticosteroids are sometimes used in specific situations such as resistance or contraindications to beta-blockers. Surgical excision can be considered in cases requiring urgent intervention such as airway obstruction; this can be done alongside laser therapies for the removal of residual tissue or when reconstructing areas of deformity. The combination of multiple treatment modalities may lead to a more rapid clinical response.

Propranolol Participates in the Treatment of Infantile Hemangioma by Inhibiting HUVECs Proliferation, Migration, Invasion, and Tube Formation

OBJECTIVE

Infantile hemangiomas (IHs) are the most common benign tumors in infancy. The purpose of this study was to study the effects of propranolol on the function of human umbilical vein endothelial cells (HUVECs), in order to preliminarily elucidate the mechanism of propranolol in the treatment of IHs.

METHODS

HUVECs were treated with different concentrations of propranolol (30 μM, 60 μM, 90 μM, and 120 μM) with or without VEGF. Their proliferation, migration, invasion, adhesion, and tube formation ability were tested by using CCK-8, wound healing assay, transwell, cell adhesion assay, and tube formation assay. The expressions of HUVECs angiogenesis signaling molecules pERK/ERK, pAKT/AKT, p-mTOR/mTOR, and pFAK/FAK were detected by Western blot.

RESULTS

Compared with the control group, propranolol could significantly inhibit the proliferation, migration, invasion, adhesion, and tube formation of HUVECs. Further studies showed that it could not only inhibit the migration, invasion, and tube formation ability of HUVECs after VEGF induction but also inhibit the phosphorylated protein expressions of angiogenesis-related signaling molecules like AKT, mTOR, ERK, and FAK in HUVECs, with a concentration-dependent inhibitory effect.

CONCLUSION

Propranolol can inhibit the proliferation, migration, invasion, adhesion, and tube formation of hemangioma endothelial cells; block VEGF-mediated angiogenesis signaling pathway; suppress the expressions of downstream angiogenesis-related signaling molecules; and ultimately achieve the effect of treatment of IHs.

15,16-dihydrotanshinone I inhibits EOMA cells proliferation by interfering in posttranscriptional processing of hypoxia-inducible factor 1

Infantile hemangioma (IH), which threatens the physical and mental health of patients, is the most common benign tumor in infants. Previously, we found that 15,16-dihydrotanshinone I (DHTS) was significantly more effective at inhibiting hemangioma proliferation in vitro and in vivo than the first-line treatment propranolol. To investigate the underlying mechanism of DHTS, we used EOMA cells as a model to study the effect of DHTS. We compared the transcriptomes of control and DHTS-treated EOMA cells. In total, 2462 differentially expressed genes were detected between the groups. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed downregulated activity of the hypoxia-inducible factor 1 alpha (HIF-1α) signaling pathway in EOMA cells following treatment with DHTS. Thus, we investigated HIF-1α expression at protein and mRNA levels. Our results revealed that DHTS downregulated HIF-1α expression by interfering in its posttranscriptional processing, and the RNA-binding protein HuR participated in this mechanism. Our findings provide a basis for clinical transformation of DHTS and insight into pathogenic mechanisms involved in IH.

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.

Serum cytokine profiles in infants with infantile hemangiomas on oral propranolol treatment: VEGF and bFGF, potential biomarkers predicting clinical outcomes

BACKGROUND

Oral propranolol has become first-line treatment for infantile hemangiomas (IHs). This study focused on identifying cytokines related to the biology of IH and early regression indicators of IH after propranolol treatment.

METHODS

For inclusion, the patients had to be aged less than 1 year and have an IH with a largest diameter ≥2 cm. Patients were scheduled to receive 1 year of propranolol treatment. Serum cytokines involved in angiogenesis, vasculogenesis, and/or chronic inflammation were analyzed at 0, 1, and/or 12 months after treatment using Multiplex Luminex assays.

RESULTS

Among the 49 evaluable patients, 33 completed the 1-year treatment: 16 showed excellent response and 12 had good response to propranolol. Significant decreases in serum MMP-2, bFGF, VEGF-α, and MCP-1 levels were observed after 1 year of treatment compared to pretreatment values. The maximal diameters of the lesions significantly correlated with pretreatment serum VEGF-α, bFGF, and MMP-9. Patients with higher bFGF and VEGF levels showed better response to propranolol at 1 year.

CONCLUSION

MMP-2, VEGF-α, bFGF, and MCP-1 may involve in the biology of IH and their downregulation may be associated with involution processes of IH. Pretreatment bFGF and VEGF could be novel biomarkers for predicting response to propranolol.

IMPACT

We found that decreases in the concentrations of MMP-2, bFGF, VEGF, and MCP-1 were associated with regression of the hemangioma, which indicates that one of the mechanisms of propranolol in the treatment of proliferative hemangiomas may involve downregulation of those cytokines. Patients with higher bFGF and VEGF levels showed better response to propranolol at 1 year. Importantly, serum bFGF higher than 37.07 pg/mL may predict an excellent response to propranolol. Therefore, along with the patient's age and the size and visual characteristics of the lesion, bFGF levels could help determine the viability of propranolol use in the treatment of IHs. Our study represented extensive serum profiling in IH, reporting the indicators and molecules clearly related to IH regression with propranolol treatment. The authors believe that monitoring serum cytokines, including MMP-2, bFGF, VEGF, and MCP-1, in IH patients could be important, in addition to clinical follow-up, for determining when to start and end propranolol treatment.

NOTCH pathway activation in infantile hemangiomas

OBJECTIVE

The objective of this study was to characterize the role of NOTCH signaling cascade activation in the angiogenic drive of infantile hemangioma (IH) tissue.

METHODS

Both IH tissue and normal skin were collected from 55 surgical patients. Of these, 14 were proliferating hemangiomas, 14 were stationary, 14 were involuted, and 13 had been treated with propranolol. Protein and RNA were extracted from all tissues and subjected to Western blotting and reverse transcription-polymerase chain reaction, respectively, for components of the NOTCH signaling pathway.

RESULTS

Compared with normal skin from the same patients, proliferating IHs contained higher levels of messenger RNA and protein for the majority of NOTCH receptors and ligands as well as the downstream coactivator MAML1. Expression of NOTCH receptor ligand messenger RNA and protein was significantly lower in involuting and propranolol-treated IHs.

CONCLUSIONS

Perturbations in NOTCH signaling follow the natural course and treatment outcome of IHs, suggesting a critical role in their pathogenesis.

Silencing long non‑coding RNA NEAT1 suppresses the tumorigenesis of infantile hemangioma by competitively binding miR‑33a‑5p to stimulate HIF1α/NF‑κB pathway

Infantile hemangioma (IH) is one of the most common vascular tumors that occurs during childhood, but its pathogenesis is currently not completely understood. Even though lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) plays vital roles in tumorigenesis of malignant tumors, its roles in IH remain unclear. Therefore, we evaluate the function of lncRNA NEAT1 in IH. Reverse transcription-quantitative PCR indicated that IH tissues exhibited high expression levels of NEAT1 and hypoxia-inducible factor 1α (HIF1α), and low expression levels of the microRNA (miR)-33a-5p. Small interfering RNA-mediated depletion of NEAT1 suppressed hemangioma endothelial cell (HemEC) proliferation, migration and invasion. The data suggested that NEAT1 positively regulated HIF1α expression by sponging miR-33a-5p in HemECs. miR-33a-5p overexpression or HIF1α silencing also acted to suppress HemEC proliferation, migration and invasion. Furthermore, the results indicated that the NEAT1/miR-33a-5p/HIF1α axis regulated the NF-κB signaling pathway. Collectively, the results revealed that depletion of lncRNA NEAT1 suppressed the tumorigenesis of IH by competitively binding miR-33a-5p and thereby stimulating the HIF1α/NF-κB signaling pathway.

β adrenergic receptor modulated signaling in glioma models: promoting β adrenergic receptor-β arrestin scaffold-mediated activation of extracellular-regulated kinase 1/2 may prove to be a panacea in the treatment of intracranial and spinal malignancy and extra-neuraxial carcinoma

Neoplastically transformed astrocytes express functionally active cell surface β adrenergic receptors (βARs). Treatment of glioma models in vitro and in vivo with β adrenergic agonists variably amplifies or attenuates cellular proliferation. In the majority of in vivo models, β adrenergic agonists generally reduce cellular proliferation. However, treatment with β adrenergic agonists consistently reduces tumor cell invasive potential, angiogenesis, and metastasis. β adrenergic agonists induced decreases of invasive potential are chiefly mediated through reductions in the expression of matrix metalloproteinases types 2 and 9. Treatment with β adrenergic agonists also clearly reduce tumoral neoangiogenesis, which may represent a putatively useful mechanism to adjuvantly amplify the effects of bevacizumab. Bevacizumab is a monoclonal antibody targeting the vascular endothelial growth factor receptor. We may accordingly designate βagonists to represent an enhancer of bevacizumab. The antiangiogenic effects of β adrenergic agonists may thus effectively render an otherwise borderline effective therapy to generate significant enhancement in clinical outcomes. β adrenergic agonists upregulate expression of the major histocompatibility class II DR alpha gene, effectively potentiating the immunogenicity of tumor cells to tumor surveillance mechanisms. Authors have also demonstrated crossmodal modulation of signaling events downstream from the β adrenergic cell surface receptor and microtubular polymerization and depolymerization. Complex effects and desensitization mechanisms of the β adrenergic signaling may putatively represent promising therapeutic targets. Constant stimulation of the β adrenergic receptor induces its phosphorylation by β adrenergic receptor kinase (βARK), rendering it a suitable substrate for alternate binding by β arrestins 1 or 2. The binding of a β arrestin to βARK phosphorylated βAR promotes receptor mediated internalization and downregulation of cell surface receptor and contemporaneously generates a cell surface scaffold at the βAR. The scaffold mediated activation of extracellular regulated kinase 1/2, compared with protein kinase A mediated activation, preferentially favors cytosolic retention of ERK1/2 and blunting of nuclear translocation and ensuant pro-transcriptional activity. Thus, βAR desensitization and consequent scaffold assembly effectively retains the cytosolic homeostatic functions of ERK1/2 while inhibiting its pro-proliferative effects. We suggest these mechanisms specifically will prove quite promising in developing primary and adjuvant therapies mitigating glioma growth, angiogenesis, invasive potential, and angiogenesis. We suggest generating compounds and targeted mutations of the β adrenergic receptor favoring β arrestin binding and scaffold facilitated activation of ERK1/2 may hold potential promise and therapeutic benefit in adjuvantly treating most or all cancers. We hope our discussion will generate fruitful research endeavors seeking to exploit these mechanisms.

Evaluation of Effect of Propranolol on Serum Vascular Endothelial Growth Factor and Tissue Inhibitor of Metalloproteinase-2 Levels in Infantile Hemangioma

Background:

Infantile hemangioma is the most common tumor of infancy. Currently, propranolol is a preferred drug for treating hemangioma. The exact mechanism of action of propranolol is not known. In this study, we attempted to assess whether propranolol has any effect on vascular endothelial growth factor (VEGF) and tissue inhibitor of metalloproteinase-2 (TIMP-2) over a period of time, and if it is there, how long it affects it.

Materials and Methods:

Propranolol was administered in the dosage of 2–3 mg/kg. The first serum sample was collected before starting the propranolol treatment. Thereafter, samples were collected at monthly intervals up to a total of six samples. The samples were assessed for TIMP-2 and VEGF using enzyme-linked immunosorbent assay kit.

Results:

The duration of this study was from June 2016 to November 2017. The total number of patients in this study was 15. Thirteen patients responded to treatment. The mean age of patients was 7.1 months. The mean value of baseline VEGF was 0.234 ± 0.059 and that of TIMP-2 was 1.338 ± 0.679. As compared to baseline value, the P value was statistically not significant in any of sequential values. In category-wise analysis, apart from statistically significant value in the 6^th month in excellent category and good response category in the 1^st month, all other values did not reveal any significant change in VEGF analysis. The analysis of TIMP-2 revealed a significant change in the levels from Sample 2 to Sample 6 in the excellent response group; however, the levels did not show a specific trend either increasing or decreasing.

Conclusion:

Despite its beneficial action in regression of hemangioma, the exact mechanism is yet to be identified. The exact duration of treatment needs further evaluation.

Progress in the treatment of infantile hemangioma

Infantile hemangioma (IH) is a common benign tumor, which mostly resolves spontaneously; however, children with high-risk IH need treatment. Currently, the recognized first-line treatment regimen for IH is oral propranolol, but research on the pathogenesis of IH has led to the identification of new therapeutic targets, which have shown good curative effects, providing more options for disease treatment. This article summarizes the applications of different medications, dosages, and routes of administration for the treatment of IH. In addition to drug therapy, this article also reviews current therapeutic options for IH such as laser therapy, surgical treatment, and observation. To provide the best treatment, therapeutic regimens for IH should be selected based on the child's age, the size and location of the lesion, the presence of complications, the implementation conditions, and the potential outcomes of the treatment.

Genetic investigation of childhood vascular tumor biology reveals pathways for therapeutic intervention

Vascular tumors are neoplasms of endothelial cells, a significant number of which present in childhood. Recent studies have examined the mutational landscape of many subtypes of vascular tumors, identifying mutations primarily within the Ras–mitogen-activated protein kinase (MAPK) pathway and providing a unique opportunity to consider targeted therapeutics. This review will summarize the current understanding of childhood vascular tumor pathobiology.

Localized infantile hemangiomas of the face and scalp: Predilection for the midline and periorbital and perioral skin

BACKGROUND/OBJECTIVES

Infantile hemangiomas are common vascular tumors. Identifying sites of predilection may provide insight into pathogenesis. Previous studies have suggested a predilection for the boundary of facial metameres. The objective was to observe patterns of localized hemangiomas on the face and scalp, determine sites of predilection, and place these patterns in a developmental context.

METHODS

A retrospective review of photographic archives at 10 Hemangioma Investigator Group pediatric dermatology centers identified localized infantile hemangiomas of the face and scalp. Heat map software was used to identify areas of predilection. Dot maps were used to assess frequency, and densities of infantile hemangiomas were compared between facial units using t-testing. The scalp was divided into quintiles to assess relative frequencies.

RESULTS

Four thousand one hundred fifty-three focal face and scalp infantile hemangiomas were mapped, of which 2962 (71%) were mapped to a frontal facial template. On the face, 73.8% (2186/2962) of hemangiomas occurred along the midline axis or perpendicularly across the ocular axis in a cross-shaped area of predilection intersecting at the glabella. Scalp hemangiomas show a predilection for the midline, with 149/295 (50.5%) noted on the top of the scalp at the midline (P < 0.001). Localized hemangiomas do not demonstrate a preferential laterality.

CONCLUSION

The distribution of localized infantile hemangiomas of the face and scalp is not random. There is preferential involvement of the midline face and scalp and the ocular axis. The regions corresponding to the boundaries between the embryonic facial segments, including the maxillary and mandibular metameres, are not accentuated in the distribution of infantile hemangiomas.

Beyond endothelial cells: Vascular endothelial growth factors in heart, vascular anomalies and placenta

Vascular endothelial growth factors regulate vascular and lymphatic growth. Dysregulation of VEGF signaling is connected to many pathological states, including hemangiomas, arteriovenous malformations and placental abnormalities. In heart, VEGF gene transfer induces myocardial angiogenesis. Besides vascular and lymphatic endothelial cells, VEGFs affect multiple other cell types. Understanding VEGF biology and its paracrine signaling properties will offer new targets for novel treatments of several diseases.

Propranolol for the treatment of vascular sarcomas

Vascular sarcomas are abnormal proliferations of endothelial cells. They range from benign hemangioma to aggressive angiosarcoma, and are characterized by dysregulated angiogenic signaling. Propranolol is a β-adrenergic receptor inhibitor that has demonstrated clinical efficacy in benign infantile hemangioma, and is now being used experimentally for more aggressive vascular sarcomas and other cancers. In this review, we discuss the use of propranolol in targeting these receptors in vascular tumors and other cancers.

Single-nucleotide polymorphisms of VEGF-A and VEGFR-2 genes and risk of infantile hemangioma

BACKGROUND

Infantile hemangioma (IH) is the most common vascular tumor of childhood and infancy. It is distinguished by rapid proliferation of endothelial cells during the first year of life followed by spontaneous regression thereafter. One of the possible factors responsible for the IH development is vascular endothelial grow factor (VEGF). The purpose of this study was to evaluate the influence of selected polymorphisms in the genes coding for VEGF-A (+405 G/C, rs2010963; +936 C/T, rs3025039) and its receptor VEGFR-2 (+1416 T/A, rs1870377; -271 G/A, rs7667298) on the susceptibility to infantile hemangioma.

METHODS

We performed a case-control study of 99 Polish children hospitalized due to IH and compared them with matched healthy control subjects. The polymorphisms were ascertained through genotyping by PCR-RFLP assay, PCR-HRM, or the allelic discrimination method.

RESULTS

The study revealed a lower odds of infantile hemangioma in individuals with GG genotype or G allele for +405 G/C VEGF-A polymorphism (OR_dis = 0.52, P = 0.023 and OR_dis  = 0.63, P = 0.025, respectively). No association was observed for the remaining VEGF and VEGFR-2 polymorphisms and IH risk.

CONCLUSIONS

In our study, none of the investigated VEGF-A and VEGFR-2 genes polymorphisms was found to be an independent prognostic marker for infantile hemangioma. However, there is evidence that individuals carrying at least one G allele of +405 G/C VEGF-A polymorphism have significantly lower risk of IH.

Curcumin induces apoptosis and inhibits proliferation in infantile hemangioma endothelial cells via downregulation of MCL-1 and HIF-1α

BACKGROUND

Curcumin has been used as an alternative medicine for the treatment of infantile hemangiomas (IHs); however, the mechanism underlying the effectiveness of curcumin in IHs remains largely unclear.

METHODS

In this study, we isolated primary human hemangioma endothelial cells (HemECs) from fresh surgical specimens of 3 patients. We treated HemECs by curcumin and investigated the alterations in proliferative and apoptotic signaling pathways with cell counting kit-8, flow cytometry, western blotting, immunofluorescence, and real-time polymerase chain reaction.

RESULTS AND CONCLUSION

We found that curcumin potently inhibited proliferation in HemECs, achieving low-micromolar IC50 (the half maximal inhibitory concentration) value. We also observed that treatment with curcumin induced apoptosis in HemECs, as evidenced by positively Annexin-V-FITC staining, caspase-3 activation, and cleavage of poly(adenosine diphosphate-ribose) polymerase (PARP) in the treated cells. Moreover, we showed that curcumin suppressed the expression of antiapoptotic protein myeloid cell leukemia-1 (MCL-1), hypoxia-inducible factor 1α (HIF-1α), and vascular endothelial growth factor (VEGF).Altogether, our study suggests that the effectiveness of curcumin in IHs may be associated with its potent antiproliferative and apoptotic activities in HemECs.

Infantile hemangioma: pathogenesis and mechanisms of action of propranolol

Infantile hemangioma (IH) is the most common benign tumor of childhood, with a prevalence of 4 % to 10 %. It is characterized by a proliferative rapid growth phase, which starts after a few weeks of life, followed by a slow regression phase. In IH cases that are potentially disfiguring or life-threatening (10 % to 15 % of all cases), systemic therapy should be promptly initiated. Data source The present study reviews published scientific articles available in reliable electronic databases. Selected were all studies that evaluated the pathogenesis of IH and the mechanisms of action of propranolol. Conclusions The pathogenesis of IH has not been fully elucidated. Studies show that, in the proliferative phase of IH, there is an imbalance of angiogenic factors and an increase in the levels of vascular endothelial growth factor and matrix metalloproteinases 2 and 9. In the regression phase, the levels of these factors decrease, whereas those of antiangiogenic factors, including tissue inhibitors of matrix metalloproteinases, increase. Since 2008, propranolol has become the drug of choice in the treatment of IH, targeting vascular tone, angiogenesis, and apoptosis. Current insights into the pathogenesis of IH allow for the development of new therapeutic strategies.

Mechanisms of Action of MicroRNAs in Infantile Hemangioma Tissue and Vascular Endothelial Cells in Different Periods

Background

The aim of this study was to investigate the developmental mechanisms of infantile hemangioma (IH) from the microRNA level.

Material/Methods

A total of 63 biological specimens of IH were obtained from the First Affiliated Hospital of Jinzhou Medical University and we assessed related miRNAs. Magnetic bead sorting, endocytosis test, canalization assay, and immunofluorescence detection were performed. The IH-derived cells were transfected with related factors and then we assessed the apoptosis and invasion.

Results

The contents of MiR-455, miR-206, and miR-29a in the proliferative period group (PP) were lower than in the complete regression period group (CR) (P<0.05), and the content of miR-29a in the regression period group (RP) was lower than in the group CR (P<0.05). The post-sorting proliferation capacity was faster than in human umbilical vein endothelial cells, and IH-derived vascular endothelial cells (VECs) exhibited faster canalization ability. The cells transfected with miR-29a exhibited obvious apoptosis 48 h later, the cells transfected with miR-206 exhibited significantly reduced proliferation capacity as well as apoptosis 48 h later, and the invasion capacity was decreased 24 h after transfection.

Conclusions

miR-29a, miR-206, and miR-455 are differently expressed in different periods of IH, and may participate in regulating multiple functions during the progression of IH.

Assessment of Infantile Hemangiomas Using a Handheld Wireless Diffuse Optical Spectroscopic Device

BACKGROUND/OBJECTIVES

Infantile hemangiomas (IHs) are vascular tumors with the potential for significant morbidity. There is a lack of validated objective tools to assess IH severity and response to treatment. Diffuse optical spectroscopy (DOS), a noninvasive, nonionizing imaging modality, can measure total hemoglobin concentration and hemoglobin oxygen saturation in tissue to assess IH vascularity and response to treatment. Our objective was to evaluate the utility of a wireless, handheld DOS system to assess IH characteristics at selected points during their clinical course.

METHODS

Thirteen subjects (initial age 5.8 ± 2.0 mos) with 15 IHs were enrolled. IHs were classified as proliferative, plateau phase, or involuting. Nine patients with 11 IHs were untreated; four patients with 4 IHs were treated with timolol or propranolol. Each IH was evaluated by placing the DOS system directly on the lesion as well a normal contralateral skin site. IH vascularity and oxygenation were scored using a newly defined normalized hypoxia fraction (NHF) coefficient. Measurements were recorded at various intervals from the initial visit to 1 to 2 years of age.

RESULTS

For the nine untreated IHs, the NHF was highest at 6 months of age, during proliferation. Differences in NHFs between the proliferation and the plateau (p = 0.02) and involuting (p < 0.001) stages were statistically significant. In treated patients, the NHF normalized to 60% after 2 months. One treated IH came within 5% of the NHF for normal skin after 12 months.

CONCLUSIONS

DOS can be used to assess the vascularity and tissue oxygenation of IHs and monitor their progression and response to treatment.

Arrested Development: Infantile Hemangioma and the Stem Cell Teratogenic Hypothesis

BACKGROUND

Early-life programming is defined by the adaptive changes made by the fetus in response to an adverse in utero environment. Infantile hemangioma (IH), a vascular anomaly, is the most common tumor of infancy. Here we take IH as the tumor model to propose the stem cell teratogenic hypothesis of tumorigenesis and the potential involvement of the immune system.

OBJECTIVES

Teratogenic agents include chemicals, heavy metals, pathogens, and ionizing radiation. To investigate the etiology and pathogenesis of IH, we hypothesized that they result from a teratogenic mechanism. Immature, incompletely differentiated, dysregulated progenitor cells (multipotential stem cells) are arrested in development with vasculogenic, angiogenic, and tumorigenic potential due to exposure to teratogenic agents such as extrinsic factors that disrupt intrinsic factors via molecular mimicry. During the critical period of immunological tolerance, environmental exposure to immunotoxic agents may harness the teratogenic potential in the developing embryo or fetus and modify the early-life programming algorithm by altering normal fetal development, causing malformations, and inducing tumorigenesis. Specifically, exposure to environmental agents may interfere with physiological signaling pathways and contribute to the generation of IH, by several mechanisms.

DISCUSSION

An adverse in utero environment no longer serves as a sustainable environment for proper embryogenesis and normal development. Targeted disruption of stem cells by extrinsic factors can alter the genetic program.

CONCLUSIONS

This article offers new perspectives to stimulate discussion, explore novel experimental approaches (such as immunotoxicity/vasculotoxicity assays and novel isogenic models), and to address the questions raised to convert the hypotheses into nontoxic, noninvasive treatments.

Association of ATF4 Expression With Tissue Hypoxia and M2 Macrophage Infiltration in Infantile Hemangioma

Accumulating studies have revealed the hypoxic condition and its crucial role in the distinctive progression of infantile hemangioma (IH), the most common benign tumor in infancy. Activating transcription factor 4 (ATF4), an important gene mediating cellular adaptation to various stress signals, could confer a survival advantage for tumor cells under hypoxia and regulate tumor progression. However, the potential role of ATF4 in IH was still unknown. In this study, the expression of hypoxia inducible factor (HIF)-1α, ATF4, and macrophage colony-stimulating factor (M-CSF) in 27 specimens of IH was measured by immunochemistry and double-labeling immunofluorescence, followed by the Spearman rank correlation test. Our results showed that the expression of HIF-1α, ATF4, and M-CSF was significantly upregulated in proliferating IH compared with involuting IH. Meanwhile, HIF-1α and ATF4, in parallel with ATF4 and M-CSF, exhibited positive correlation and synchronous expression. In addition, our in vitro studies demonstrated that hypoxia obviously upregulated the expression of HIF-1α, ATF4, and M-CSF in hemangioma stem cells. Most importantly, their expression was uniformly correlated with the percentage of M2-polarized macrophages in IH. All those results and established evidence indicated that hypoxia-induced ATF4 expression may promote progression of proliferating IH through M-CSF-induced M2-polarized macrophages infiltration.

Gender, Estrogen, and Obliterative Lesions in the Lung

Gender has been shown to impact the prevalence of several lung diseases such as cancer, asthma, chronic obstructive pulmonary disease, and pulmonary arterial hypertension (PAH). Controversy over the protective effects of estrogen on the cardiopulmonary system should be of no surprise as clinical trials of hormone replacement therapy have failed to show benefits observed in experimental models. Potential confounders to explain these inconsistent estrogenic effects include the dose, cellular context, and systemic versus local tissue levels of estrogen. Idiopathic PAH is disproportionately found to be up to 4 times more common in females than in males; however, estrogen levels cannot explain why males develop PAH sooner and have poorer survival. Since the sex steroid hormone 17β-estradiol is a mitogen, obliterative processes in the lung such as cell proliferation and migration may impact the growth of pulmonary tissue or vascular cells. We have reviewed evidence for biological differences of sex-specific lung obliterative lesions and highlighted cell context-specific effects of estrogen in the formation of vessel lumen-obliterating lesions. Based on this information, we provide a biological-based mechanism to explain the sex difference in PAH severity as well as propose a mechanism for the formation of obliterative vascular lesions by estrogens.