Basic science and clinical aspects of vascular anomalies

Integrated WGCNA and PPI Network to Screen Hub Genes Signatures for Infantile Hemangioma

BACKGROUND

Infantile hemangioma (IH) is characterized by proliferation and regression.

METHODS

Based on the GSE127487 dataset, the differentially expressed genes (DEGs) between 6, 12, or 24 months and normal samples were screened, respectively. STEM software was used to screen the continued up-regulated or down-regulated in common genes. The modules were assessed by weighted gene co-expression network analysis (WGCNA). The enrichment analysis was performed to identified the biological function of important module genes. The area under curve (AUC) value and protein-protein interaction (PPI) network were used to identify hub genes. The differential expression of hub genes in IH and normal tissues was detected by qPCR.

RESULTS

There were 5,785, 4,712, and 2,149 DEGs between 6, 12, and 24 months and normal tissues. We found 1,218 DEGs were up-regulated or down-regulated expression simultaneously in common genes. They were identified as 10 co-expression modules. Module 3 and module 4 were positively or negatively correlated with the development of IH, respectively. These two module genes were significantly involved in immunity, cell cycle arrest and mTOR signaling pathway. The two module genes with AUC greater than 0.8 at different stages of IH were put into PPI network, and five genes with the highest degree were identified as hub genes. The differential expression of these genes was also verified by qRTPCR.

CONCLUSION

Five hub genes may distinguish for proliferative and regressive IH lesions. The WGCNA and PPI network analyses may help to clarify the molecular mechanism of IH at different stages.

Oncosuppressors and Oncogenes: Role in Haemangioma Genesis and Potential for Therapeutic Targeting

Genetic lesions in proto-oncogenes result in the perturbation of angiogenesis, the formation of neovessels from a pre-existing microvasculature. Similarly, the subversion of tumor suppressor genes promotes tumor vascularization. Excessive neovessel formation is associated with various neoplasms such as infantile hemangiomas (IH). Hemangiomas are the most common tumors in pediatric patients and at present have no definitive treatment. The pathogenesis of IH is not well understood; however, both vasculogenesis and angiogenesis are associated with hemangioma genesis. A number of factors that modulate angiogenesis and vasculogenesis have been shown to be dysregulated in IH. Several of the oncogenes and tumor suppressors linked to the promotion of angiogenesis are also altered in infantile hemangioma. In this review, the roles of oncogenes and tumor suppressor genes during neovascularization and hemangioma genesis are explored. In addition, the potential for targeting these genes in IH therapy is discussed.

Treatment with propranolol for infantile hemangiomas: A case series of 106 infants

The aim of the present study was to investigate the clinical benefit and side effects of propranolol treatment in 106 children with infantile hemangiomas (IHs). A retrospective chart review was conducted on all children who attended the clinic between September 16, 2009 and November 11, 2013. Propranolol was administered in a progressive schedule reaching 1.0-1.5 mg/kg/day, divided into three doses. Demographic data, clinical features, imaging, treatment regimens and outcomes were investigated. Any adverse effects following medication were evaluated and managed accordingly. Preliminary analysis of the data showed the inclusion of 106 children (71 female and 35 male) with a mean age and weight at onset of treatment of 5.1 months and 7.3 kg, respectively. All 106 patients responded positively to treatment. Side effects that required intervention and/or close monitoring included diarrhea (n=10), hypotension (n=7), nightmares (n=2), agitation (n=1) and cold extremities (n=1). No long-term adverse effects were observed in any of the patients. In conclusion, propranolol administered orally at 1.0-1.5 mg/kg/day had a rapid therapeutic effect for resolving IHs with few complications.

The MET gene is a common integration target in avian leukosis virus subgroup J-induced chicken hemangiomas

Avian leukosis virus subgroup J (ALV-J) is a simple retrovirus that can cause hemangiomas and myeloid tumors in chickens and is currently a major economic problem in Asia. Here we characterize ALV-J strain PDRC-59831, a newly studied U.S. isolate of ALV-J. Five-day-old chicken embryos were infected with this virus, and the chickens developed myeloid leukosis and hemangiomas within 2 months after hatching. To investigate the mechanism of pathogenesis, we employed high-throughput sequencing to analyze proviral integration sites in these tumors. We found expanded clones with integrations in the MET gene in two of the five hemangiomas studied. This integration locus was not seen in previous work characterizing ALV-J-induced myeloid leukosis. MET is a known proto-oncogene that acts through a diverse set of signaling pathways and is involved in many neoplasms. We show that tumors harboring MET integrations exhibit strong overexpression of MET mRNA.

IMPORTANCE

These data suggest that ALV-J induces oncogenesis by insertional mutagenesis, and integrations in the MET oncogene can drive the overexpression of MET and contribute to the development of hemangiomas.

Vascular anomalies of the hand and wrist

Vascular malformations of the hand and wrist are uncommon. They develop from aberrations in angiogenic signaling during vascular development. Unlike hemangiomas, which are characterized by biphasic growth and slow spontaneous involution, vascular malformations continue to grow proportionally with the child. Management is dictated by classification of the vascular malformations, which is based on flow characteristics (ie, low, high) and predominant cell type (ie, venous, lymphatic, capillary, combined, arteriovenous). Initial management is conservative, with the goal of providing relief from pain and swelling. Sclerotherapy, laser treatment, and arterial embolization may be beneficial in well-selected patients. Surgery is indicated in cases of persistent pain and uncontrolled limb swelling leading to functional impairment and/or neurologic compression. The goals of surgery are to excise as much of the lesion as possible while avoiding injury to adjacent nerves, minimizing blood loss, and preventing distal limb ischemia. This mandates careful preoperative planning and meticulous technique. Adjuvant treatments may be warranted, as in the case of preoperative embolization in patients with high-flow lesions.

Inhibition of angiogenesis mediated by extremely low-frequency magnetic fields (ELF-MFs)

The formation of new blood vessels is an essential therapeutic target in many diseases such as cancer, ischemic diseases, and chronic inflammation. In this regard, extremely low-frequency (ELF) electromagnetic fields (EMFs) seem able to inhibit vessel growth when used in a specific window of amplitude. To investigate the mechanism of anti-angiogenic action of ELF-EMFs we tested the effect of a sinusoidal magnetic field (MF) of 2 mT intensity and frequency of 50 Hz on endothelial cell models HUVEC and MS-1 measuring cell status and proliferation, motility and tubule formation ability. MS-1 cells when injected in mice determined a rapid tumor-like growth that was significantly reduced in mice inoculated with MF-exposed cells. In particular, histological analysis of tumors derived from mice inoculated with MF-exposed MS-1 cells indicated a reduction of hemangioma size, of blood-filled spaces, and in hemorrhage. In parallel, in vitro proliferation of MS-1 treated with MF was significantly inhibited. We also found that the MF-exposure down-regulated the process of proliferation, migration and formation of tubule-like structures in HUVECs. Using western blotting and immunofluorescence analysis, we collected data about the possible influence of MF on the signalling pathway activated by the vascular endothelial growth factor (VEGF). In particular, MF exposure significantly reduced the expression and activation levels of VEGFR2, suggesting a direct or indirect influence of MF on VEGF receptors placed on cellular membrane. In conclusion MF reduced, in vitro and in vivo, the ability of endothelial cells to form new vessels, most probably affecting VEGF signal transduction pathway that was less responsive to activation. These findings could not only explain the mechanism of anti-angiogenic action exerted by MFs, but also promote the possible development of new therapeutic applications for treatment of those diseases where excessive angiogenesis is involved.

The potential of capillary birthmarks as a significant marker for capillary malformation-arteriovenous malformation syndrome in children who had nontraumatic cerebral hemorrhage

BACKGROUND/PURPOSE

Capillary malformation-arteriovenous malformation (CM-AVM) is a new autosomal dominant disorder with cutaneous capillary malformations (CM) and high-flow cerebral arteriovenous malformations (AVM). Patients may have Parkes-Weber syndrome. This study determined if cutaneous CM are a significant indicator of CM-AVM in children with cerebral bleeds.

METHODS

Children with cerebral AVMs between 1991 and 2009 were reviewed. A family history of brain hemorrhage, AVMs, or cutaneous birthmarks was elicited. Patients and siblings were examined for CM and a family tree recorded. A brief questionnaire determined the family's opinion regarding screening for this syndrome.

RESULTS

Of 30 families, 1 family had Parkes-Weber syndrome. In 3 families, both patient and relatives had CM. In 9 families, patients had no CM, but relatives had them. One family had hereditary hemorrhagic telangiectasia. From the survey, 80% of families would be concerned about vascular marks, and 87% of families would allow screening for cerebral AVMs.

CONCLUSION

A family history of vascular marks may predict families at risk of having a cerebral AVM with hemorrhage. Most families would agree to screening. However, family history and physical examination alone do not confirm CM-AVM but form a useful screening tool to identify families needing further investigations with genetic testing and/or magnetic resonance imaging.

Vascular anomalies of the upper extremity

The topic of vascular anomalies is uncommon in the hand surgery literature, but hand surgeons do diagnose and treat patients with hemangiomas and vascular malformations. These are separate entities and require different treatment strategies. Proper diagnosis will lead to timely and appropriate treatment.

Kasabach-Merritt phenomenon: a single centre experience

OBJECTIVE

Kasabach-Merritt phenomenon (KMP) can lead to life-threatening bleeding, and its optimum treatment has not been established. We review the experience of managing KMP in a single institution.

METHODS

A retrospective chart review on all children with KMP treated at the Hospital for Sick Children, Toronto, over an 18 yr period was carried out.

RESULTS

All 15 patients had profound thrombocytopenia and hypofibrinogenemia at presentation, half had bleeding symptoms, and three had cardiac failure. All patients received corticosteroids. Five responded to steroids alone, given for an average of 13 wk, increasing platelets to >20 x 10(9)/L at a mean of 6.2 d and fibrinogen >1 g/dL at 25.6 d. Ten patients received at least one other therapeutic modality in addition to steroids, including vincristine, interferon, anti-platelet agents and pentoxifylline. Five patients received vincristine, for a mean of 6 wk, with two patients responding. Eight patients received interferon, for a mean of 4 months, with two patients responding. Overall, the mean time to increasing platelets >20 x 10(9)/L was 56 d, to >150 x 10(9)/L was 88 d and fibrinogen >1 g/dL 49 d. Ten patients showed a partial response to embolisation, with a mean of 2.8 procedures performed. Thrombotic complications occurred in 7%. Twelve patients remain alive, with relapse in six patients, all treated successfully. One patient died, and two patients have been lost to follow-up.

CONCLUSION

KMP is a rare condition, with significant morbidity and mortality. The therapeutic approach should include a multidisciplinary team and consensus on guidelines.

Serum levels of vascular endothelial growth factor and basic fibroblastic growth factor in children with hemangiomas and vascular malformations--preliminary report

Impaired balance between proangiogenic and antiangiogenic factors has been implicated in the development of hemangiomas. Elevated vascular endothelial growth factor serum levels and basic fibroblastic growth factor urine levels in patients with proliferating hemangiomas were reported. However, whether these growth factors can be used for the differential diagnosis of vascular anomalies or assessment of the clinical course of hemangiomas has yet to be determined. We report here our preliminary results of serum vascular endothelial growth factor and basic fibroblastic growth factor levels as an aid in the diagnosis of hemangiomas and in the follow up of patients with this lesion. Twenty two children with infantile hemangioma (13 with proliferating hemangiomas, nine with involuting lesions), five children with vascular malformations, and 25 healthy children study group. Vascular endothelial growth factor and basic fibroblastic growth factor serum levels were analyzed by an ELISA assay. The serum vascular endothelial growth factor concentrations in children with proliferating hemangiomas were significantly higher than in patients with involuting hemangiomas, vascular malformations and healthy patients. The serum basic fibroblastic growth factor concentrations were low and similar in all patients with no statistical correlation between study groups. We concluded that (i) ELISA can easily determine vascular endothelial growth factor concentrations in different phases of hemangioma growth and help distinguishing them from vascular malformations. (ii) A potential role for vascular endothelial growth factor in the pathophysiology of hemangiomas is probable.

Group A streptococcal infection of an intramuscular venous malformation: a case report and review of the literature

Intramuscular venous malformations are uncommon benign masses of vascular origin that can occur anywhere in the body. They can be small and clinically insignificant or can be large and violate tissue planes and viscera. Presentation is as variable as the extent of the lesions. They can be diagnosed as a result of local pain and swelling or as incidental findings. Rarely, venous malformations can get infected and present with fever or other more severe systemic symptoms. The literature is sparse regarding infection of intramuscular venous malformations. This case describes the presentation, diagnosis, and management of a patient with group A streptococcal infection of a previously undiagnosed intramuscularvenous malformation in a patient who presented to our pediatric emergency department.

Histopathological reporting of paediatric cutaneous vascular anomalies in relation to proposed multidisciplinary classification system

BACKGROUND

The terminology applied to vascular anomalies has been variable in previously published literature making interpretation suboptimal. The International Society for the Study of Vascular Anomalies (ISSVA) has proposed a revised classification based on clinical features and histopathological findings. This classification is increasingly being accepted as clinically useful and a platform for future studies.

AIMS

To examine the extent to which the ISSVA classification can be practically applied to diagnostic histopathological specimens.

METHODS

Cutaneous vascular lesions received in a single paediatric pathology unit during a 2-year period (2004-5) were reviewed, including glucose transporter protein 1 (GLUT1) immunostaining where required, and lesions were reclassified according to the ISSVA classification.

RESULTS

144 specimens were identified. Appropriate full clinical information was provided in only 17% of cases at submission. Infantile haemangiomas comprised 46% of cases, 18% of which were regressive type, initially inaccurately identified as vascular malformations before GLUT1 immunostaining. 30% of lymphatic malformations and all lymphovenous malformations were previously classified as vascular malformations, not otherwise specified.

CONCLUSIONS

The ISSVA classification of vascular anomalies provides a useful framework for histopathologists to classify vascular anomalies. However, meaningful and appropriate use of such a system is dependent on the adequacy of clinical information provided and routine use of immunohistochemical markers.