Biomedicine and diseases: the Klippel-Trenaunay syndrome, vascular anomalies and vascular morphogenesis

Angiogenic factor AGGF1 is a general splicing factor regulating angiogenesis and vascular development by alternative splicing of SRSF6

AGGF1 encodes an angiogenic factor that causes vascular disease Klippel-Trenaunay syndrome when mutated. AGGF1 also acts at the top of the genetic regulatory hierarchy for mesodermal differentiation of hemangioblasts, multipotent stem cells for differentiation of blood cells and vascular cells. Alternative splicing (AS) is a post-transcriptional process that generates multiple mature mRNAs from a single primary transcript (pre-mRNA), producing protein diversity. Deregulation of AS leads to many human diseases. The physiological role and mechanism of AGGF1 in AS are not clear. Full-length transcriptome sequencing of human pulmonary artery endothelial cells (HPAECs) with AGGF1 silencing revealed 63 121 genes, including 1144 new unannotated genes, and showed that AGGF1 is a general splicing factor regulating AS of 436 genes, including SRSF6 regulating AS of many target genes. AGGF1 promoted the skipping of exon 3 that produces the full-length SRSF6 protein, an evolutionarily conserved AS event. Overexpression of full-length SRSF6 reversed the reduced cell proliferation, migration, and capillary tube formation of HPAECs with AGGF1 silencing. Knockdown of SRSF6 and overexpression of the shorter, alternatively spliced isoform of SRSF6 both inhibited HPAEC proliferation, migration, and capillary tube formation, whereas opposite results were obtained for overexpression of full-length SRSF6. Knockdown of srsf6 impaired development of ISVs in zebrafish, whereas overexpression of srsf6 enhanced vascular development and partially rescued impaired ISV development in zebrafish embryos with aggf1 knockdown. Overall, our findings reveal that AGGF1 is a general splicing factor, and that AGGF1-mediated exon 3 skipping of SRSF6 pre-mRNA is important for endothelial cell functions, angiogenesis, and vascular development.

Klippel-Trénaunay-Weber Syndrome: Prenatal Diagnosis and Review of the Literature

Klippel-Trénaunay-Weber syndrome (KTW) is a rare congenital disease, representing a challenge in prenatal diagnosis due to overlapping characteristics with other syndromes and no specific genetic markers known to date. We have collected all the cases present in the literature on the prenatal diagnosis of KTW, emphasizing common ultrasound findings that can guide the clinician and genetics to the prenatal counseling. Thus, we collected all the information about the postnatal prognosis and the necessity for treatment. Our review of 44 cases highlights the typical common features: hemihypertrophy, predominantly affecting the right leg, with cystic lesions extending to the trunk or upper limbs and rare internal organ involvement. Prenatal complications, including hydrops and polyhydramnios, emphasize the need for a careful ultrasound follow-up. Despite no identified genetic mutation, genetic counseling and invasive testing are recommended. Mortality rate due to a severe complication known as Kasabach-Merritt syndrome, underlines the importance of early diagnosis and accurate management strategies. Prenatal diagnosis of KTW, guided by ultrasound findings and genetic counseling, could help with informed decision-making and optimal care planning.

Radiation-Induced Angiosarcoma in a Patient With Klippel-Trenaunay Syndrome: A Case Report

Background

Klippel-Trenaunay syndrome (KTS) is a rare vascular disorder that typically presents in the lower limb with unilateral port-wine discoloration of the skin due to capillary malformations, varicose veins, and soft tissue and bone overgrowth. Radiation-induced angiosarcoma (RIAS) is a rare vascular malignancy that develops as a long-term complication secondary to radiation therapy. While there is no well-established direct relationship between KTS and development of angiosarcoma, there is literature that suggests a logical association between the 2 disorders. The present case report highlights the importance of further research into a potential connection between KTS and RIAS.

Methods

A 51-year-old female with a history of KTS was referred to the plastic surgery clinic for delayed breast reconstruction following RIAS of the left breast. It was decided that a 2-stage left latissimus dorsi musculocutaneous flap reconstruction with silicone implant would best achieve her goal of symmetry.

Results

The patient reported here had an unremarkable postoperative course. Of note, this patient experienced severe body dysmorphia after her mastectomy and RIAS excision due to the absence of her left breast juxtaposed with her prior large right breast augmentation. The choice of 2-stage combined autologous/implant reconstruction likely contributed to her satisfactory cosmetic outcome.

Conclusions

While RIAS and KTS are distinct conditions, a link may exist between the two. More research is needed to investigate this possible relationship. Aggressive treatment of RIAS is crucial for patient recovery, and a 2-stage combined autologous/implant reconstruction is an optimal choice for post-RIAS reconstruction, especially in patients hoping to achieve a large breast size.

New Insights into Cervicofacial Vascular Anomalies

Congenital cervicofacial vascular anomalies are extremely rare and present many difficulties in diagnosis and treatment requiring a multidisciplinary approach. Firstly, there is little consensus on this subject among head and neck specialists. There are two main types of vascular anomalies: vascular tumors and vascular malformations. Vascular malformations are also divided into malformations with slow blood flow (veins, lymphatics, capillaries or combined) and malformations with a fast blood flow (arteriovenous malformations and fistula). Vascular tumors like hemangiomas are known for their spontaneous involution with aging, while vascular malformations grow in dimensions with age. It is very important to choose the correct differential diagnosis between cervicofacial hemangiomas and vascular malformations for proper therapy management. Anamnesis and clinical exams help in raising suspicions about the real nature of a cervico-vascular anomaly. Furthermore, imaging brings in-depth details of the anomaly, ranging from ultrasound and contrast CT to MRI scanning and minimally invasive angiography. Angiography with selective embolization is rarely a curative procedure for arteriovenous malformations, being more suitable as a preliminary step before attempted surgical removal. Surgery is clearly necessary when there are aesthetic and functional deficits. Slow-flow vascular malformations present a reduced morbidity, and in cases without involution, the surgical ablation is reserved for the cases with aesthetic dysfunctions or psychological trauma. Lymphatic malformations must undergo surgical ablation when they are associated with mass effects and compression of great vessels or aerial viscera. The prognosis after surgical removal is good, with a low rate of recurrence or morbidity. Fast-flow vascular malformations require a combined approach, with embolization and excision in the next 48 h for safety reasons. Removal may be followed by reconstructive surgery depending on the location and dimensions of the malformation, with a possible secondary recovery of the normal microscopic vessels. Some of the masses may hinder the normal airflow and swallowing. Pathology is the gold standard for confirming the clinical and imaging diagnosis.

A Rare Case of Klippel Trenaunay Syndrome with Von Willebrand Factor Deficiency and Multiple Accessory Spleens: A Case Report and Brief Literature Review

Klippel Trenaunay Syndrome (KTS) is an uncommon inherited syndrome identified by venous varicosities and capillary abnormalities. von Willebrand Disease is the most common inherited hemorrhage disturbance in humans, leading to insufficiency in von Willebrand Factor, which is a complex multimeric protein with two functions: it forms a bridge between the platelets and injured vascular areas and it attaches factor VIII and stabilizes it. We present a 13-year-old son with a typical clinical manifestation of KTS, including "port-wine stains" as capillary malformation, venous malformation, and hypertrophy of the left lower extremity, who also suffers from von Willebrand Disease type 3. He has been suffering from these two rare conditions since birth. The occurrence of KTS with von Willebrand Factor deficiency in a patient has so far not been reported, which may propose a mutation in the putative common regulatory gene that caused this uncommon phenotype.

Total knee arthroplasty in patients with Klippel Trenaunay syndrome and knee osteoarthritis: A case report and a literature review

INTRODUCTION

Klippel Trenaunay syndrome (KTS) is a rare congenital disorder characterized by wine staining, varicose veins, bone hypertrophy, and soft tissue hyperplasia. KTS usually occurs at birth, early infancy or childhood. The rarity of disease makes it difficult to calculate its incidence rate. However, few studies report the incidence rate of 2 to 5 cases per 100 thousand. Furthermore, evidence demonstrates that KTS is more prevalent among males compared to females.

CASE PRESENTATION

An elderly male aged 67, was admitted to the hospital for chronic pain in his left knee. An outpatient physical examination reveals a significantly thicker left lower limb accompanied by multiple varicose veins. The right lower limb was 2 cm short on the opposite side, and the right foot was stunted with high arch deformity. The entire body was covered in a red grape globus, which faded after pressing. He was diagnosed with KTS. We performed TKA for him after blood coagulation examination. The patient recovered well after the operation. He was followed up for 1 year, The patient is in good condition and satisfied with the operation.

CONCLUSION

For patients with KTS, total knee arthroplasty is an effective surgical procedure to treat arthritis. However, some risks must be considered, and appropriate surgical preparation must be undertaken.

Klippel-Trénaunay Syndrome and Developmental Coxa Vara in the Same Limb: A Case Report with a Review of the Literature

We present a case of a 14-year-old girl who was first treated when she was 4 years old. She had progressive limping of the left lower limb from the age of 3 years. She was diagnosed to have developmental coxa vara of the left hip and treated by a subtrochanteric valgus osteotomy of the left femur. Later, she developed hypertrophy of the left upper and lower limbs. There were port-wine stains over the left lower limbs with multiple superficial varicosities. Her diagnosis was Klippel-Trénaunay syndrome (KTS). She is asymptomatic at the final follow-up. Both developmental coxa vara and KTS are rare conditions. We present this case to demonstrate the rarest combination of two rare conditions occurring in the same limb.

Aggf1 Specifies Hemangioblasts at the Top of Regulatory Hierarchy via Npas4l and mTOR-S6K-Emp2-ERK Signaling

BACKGROUND

Hemangioblasts are mesoderm-derived multipotent stem cells for differentiation of all hematopoietic and endothelial cells in the circulation system. However, the underlying molecular mechanism is poorly understood.

METHODS

CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (type II CRISPR RNA-guided endonuclease) editing was used to develop aggf1-/- and emp2-/- knockout zebra fish. Whole-mount in situ hybridization and transgenic Tg(gata1-EGFP [enhanced green fluorescent protein]), Tg(mpx-EGFP), Tg(rag2-DsRed [discosoma sp. red fluorescent protein]), Tg(cd41-EGFP), Tg(kdrl-EGFP), and Tg(aggf1-/-;kdrl-EGFP) zebra fish were used to examine specification of hemangioblasts and hematopoietic stem and progenitor cells (HSPCs), hematopoiesis, and vascular development. Quantitative real-time polymerase chain reaction and Western blot analyses were used for expression analysis of genes and proteins.

RESULTS

Knockout of aggf1 impaired specification of hemangioblasts and HSPCs, hematopoiesis, and vascular development in zebra fish. Expression of npas4l/cloche-the presumed earliest marker for hemangioblast specification-was significantly reduced in aggf1-/- embryos and increased by overexpression of aggf1 in embryos. Overexpression of npas4l rescued the impaired specification of hemangioblasts and HSPCs and development of hematopoiesis and intersegmental vessels in aggf1-/- embryos, placing aggf1 upstream of npas4l in hemangioblast specification. To identify the underlying molecular mechanism, we identified emp2 as a key aggf1 downstream gene. Similar to aggf1, emp2 knockout impaired the specification of hemangioblasts and HSPCs, hematopoiesis, and angiogenesis by increasing the phosphorylation of ERK1/2 (extracellular signal-regulated protein kinase 1/2). Mechanistic studies showed that aggf1 knockdown and knockout significantly decreased the phosphorylated levels of mTOR (mammalian target of rapamycin) and p70 S6K (ribosomal protein S6 kinase), resulting in reduced protein synthesis of Emp2 (epithelial membrane protein 2), whereas mTOR activator MHY1485 (4,6-dimorpholino-N-(4-nitrophenyl)-1,3,5-triazin-2-amine) rescued the impaired specification of hemangioblasts and HSPCs and development of hematopoiesis and intersegmental vessels and reduced Emp2 expression induced by aggf1 knockdown.

CONCLUSIONS

These results indicate that aggf1 acts at the top of npas4l and becomes the earliest marker during specification of hemangioblasts. Our data identify a novel signaling axis of Aggf1 (angiogenic factor with G-patch and FHA domain 1)-mTOR-S6K-ERK1/2 for specification of hemangioblasts and HSPCs, primitive and definitive hematopoiesis, and vascular development. Our findings provide important insights into specification of hemangioblasts and HSPCs essential for the development of the circulation system.

Rare presentation of angiomatosis in the paranasal sinuses mimicking juvenile nasopharyngeal angiofibroma in a 16 year old male

Rare presentation of pediatric angiomatosis of the paranasal sinus and skull base presenting mimicking juvenile nasopharyngeal angiofibroma (JNA). This is a 16-year-old male who presented to the emergency room with acutely worsening headaches, decreased visual acuity, subjective diplopia on lateral gaze, and a skull base mass centered in the sphenoid cavity. Endoscopic biopsy at an outside facility was aborted due to profuse bleeding. Upon transfer to a tertiary care center, contrast MR demonstrated a heterogeneously and avidly enhancing vascular mass centered around the sphenoid and skull base originating from the internal maxillary artery with significant bilateral extension into the adjacent paranasal sinuses, sella, and cavernous sinus. History of presentation and imaging was suggestive of JNA. Patient underwent preoperative embolization followed by endoscopic endonasal transphenoidal resection with a skull base trained otolaryngologist and neurosurgeon. Final pathology confirmed angiomatosis. This is only the second reported case of paranasal sinus angiomatosis in the literature. Angiomatosis has a high rate of recurrence and failure of timely diagnosis can lead to requirement of repeated surgical intervention. Re-operations are associated with increased costs, patient dissatisfaction, and poorer surgical/clinical outcomes. Because angiomatosis can mimic JNA, hemangiomas, or other vascular tumors, it is essential to maintain a broad differential diagnosis that includes angiomatosis when evaluating sinonasal tumors.

Identification and characterization of a special type of subnuclear structure: AGGF1-coated paraspeckles

AGGF1 is an angiogenic factor with G-Patch and FHA domains 1 described by our group. Gain-of-function mutations in AGGF1 cause Klippel-Trenaunay syndrome, whereas somatic loss-of-function mutations cause cancer. Paraspeckles are small membraneless subnuclear structures with a diameter of 0.5-1 μm, and composed of lncRNA NEAT1 as the scaffold and three core RNA-binding proteins NONO, PSPC1, and PSF. Here, we show that AGGF1 is a key regulatory and structural component of paraspeckles that induces paraspeckle formation, forms an outside rim of paraspeckles, wraps around the NONO/PSF/PSPC1/NEAT1 core, and regulates the size and number of paraspeckles. AGGF1-paraspeckles are larger (>1 μm) than conventional paraspeckles. RNA-FISH in combination with immunostaining shows that AGGF1, NONO, and NEAT1_2 co-localize in 20.58% of NEAT1_2-positive paraspeckles. Mechanistically, AGGF1 interacts with NONO, PSF, and HNRNPK, and upregulates NEAT1_2, a longer, 23 kb NEAT1 transcript with a key role in regulation of paraspeckle size and number. RNA-immunoprecipitation shows that AGGF1 interacts with NEAT1, which may be another possible mechanism underlying the formation of AGGF1-paraspeckles. NEAT1_2 knockdown reduces the number and size of AGGF1-paraspeckles. Functionally, AGGF1 regulates alternative RNA splicing as it decreases the exon skipping/inclusion ratio in a CD44 model. AGGF1 is also localized in some nuclear foci without NEAT1 or NONO, suggesting that AGGF1 is an important liquid-liquid phase separation (LLPS) driver for other types of AGGF1-positive nuclear condensates (referred to as AGGF1-bodies). Our results identify a special type of AGGF1-coated paraspeckles and provide important insights into the formation, structure, and function of paraspeckles.

The Klippel-Trénaunay Syndrome in 2022: Unravelling Its Genetic and Molecular Profile and Its Link to the Limb Overgrowth Syndromes

The Klippel-Trénaunay syndrome is an unusual syndrome of vascular and dermatologic manifestation in which patients demonstrate hemihypertrophy of the soft tissue and bones of one limb, cutaneous haemangiomas and varicosities in anatomically abnormal positions. Described in 1900 by two French physicians, the etiology remained unclear until recently, when evidence emerged that there was a genetic basis for this sporadic disorder. Genes that encoded pathological angiogenic factors and caused vascular dysmorphogenesis, explaining the molecular bases of this syndrome, were identified. Several angiogenic genes were identified but one gene, the AGGF1 (formerly VG5Q) gene, was seen in mutations involving patients diagnosed with Klippel-Trénaunay syndrome. Furthermore, this syndrome was also noted to have overlapping clinical features linked with the “overgrowth syndromes,” in which genetic mutations along somatic lines were identified. These involved The PI3K enzyme which forms part of the phosphoinositide 3–kinase pathway which is encoded by the PIK3CA-gene. This enzyme mediates embryonic cellular growth in-utero and diseases involved in this pathway are classified as members of the PIK3CA-related overgrowth syndrome. This paper reviews the status of what is now known about the molecular genetics of this unusual, but clinically challenging disorder and its differentiation from similar diseases, linked with the PIK3CA-gene and the related overgrowth syndromes.

Receptor and Molecular Mechanism of AGGF1 Signaling in Endothelial Cell Functions and Angiogenesis

Objective

Angiogenic factor AGGF1 (angiogenic factor with G-patch and FHA [Forkhead-associated] domain 1) promotes angiogenesis as potently as VEGFA (vascular endothelial growth factor A) and regulates endothelial cell (EC) proliferation, migration, specification of multipotent hemangioblasts and venous ECs, hematopoiesis, and vascular development and causes vascular disease Klippel-Trenaunay syndrome when mutated. However, the receptor for AGGF1 and the underlying molecular mechanisms remain to be defined.

Approach and Results

Using functional blocking studies with neutralizing antibodies, we identified [alpha]5[beta]1 as the receptor for AGGF1 on ECs. AGGF1 interacts with [alpha]5[beta]1 and activates FAK (focal adhesion kinase), Src (proto-oncogene tyrosine-protein kinase), and AKT (protein kinase B). Functional analysis of 12 serial N-terminal deletions and 13 C-terminal deletions by every 50 amino acids mapped the angiogenic domain of AGGF1 to a domain between amino acids 604-613 (FQRDDAPAS). The angiogenic domain is required for EC adhesion and migration, capillary tube formation, and AKT activation. The deletion of the angiogenic domain eliminated the effects of AGGF1 on therapeutic angiogenesis and increased blood flow in a mouse model for peripheral artery disease. A 40-mer or 15-mer peptide containing the angiogenic domain blocks AGGF1 function, however, a 15-mer peptide containing a single amino acid mutation from -RDD- to -RGD- (a classical RGD integrin-binding motif) failed to block AGGF1 function.

Conclusions

We have identified integrin [alpha]5[beta]1 as an EC receptor for AGGF1 and a novel AGGF1-mediated signaling pathway of [alpha]5[beta]1-FAK-Src-AKT for angiogenesis. Our results identify an FQRDDAPAS angiogenic domain of AGGF1 crucial for its interaction with [alpha]5[beta]1 and signaling.

Role of epigenetic m6 A RNA methylation in vascular development: mettl3 regulates vascular development through PHLPP2/mTOR-AKT signaling

N⁶ -methyladenosine (m6A) methylation is the most prevalent RNA modification, and it emerges as an important regulatory mechanism of gene expression involved in many cellular and biological processes. However, the role of m⁶ A methylation in vascular development is not clear. The m⁶ A RNA methylation is regulated by dynamic interplay among methyltransferases, binding proteins, and demethylases. Mettl3 is a member of the mettl3-mettl14 methyltransferase complex, referred to as writers that catalyze m6A RNA methylation. Here, we used CRISPR-Cas9 genome editing to develop two lines of knockout (KO) zebrafish for mettl3. Heterozygous mettl3^+/- KO embryos show defective vascular development, which is directly visible in fli-EGFP and flk-EGFP zebrafish. Alkaline phosphatase staining and whole mount in situ hybridization with cdh5, and flk markers demonstrated defective development of intersegmental vessels (ISVs), subintestinal vessels (SIVs), interconnecting vessels (ICVs) and dorsal longitudinal anastomotic vessels (DLAV) in both heterozygous mettl3^+/- and homozygous mettl3^-/- KO zebrafish embryos. Similar phenotypes were observed in zebrafish embryos with morpholino knockdown (KD) of mettl3; however, the vascular defects were rescued fully by overexpression of constitutively active AKT1. KD of METTL3 in human endothelial cells inhibited cell proliferation, migration, and capillary tube formation. Mechanistically, mettl3 KO and KD significantly reduced the levels of m⁶ A RNA methylation, and AKT phosphorylation (S473) by an increase in the expression of phosphatase enzyme PHLPP2 and reduction in the phosphorylation of mTOR (S2481), a member of the phosphatidylinositol 3-kinase-related kinase family of protein kinases. These data suggest that m⁶ A RNA methylation regulates vascular development via PHLPP2/mTOR-AKT signaling.

Vessel-on-a-chip models for studying microvascular physiology, transport, and function in vitro

To understand how the microvasculature grows and remodels, researchers require reproducible systems that emulate the function of living tissue. Innovative contributions toward fulfilling this important need have been made by engineered microvessels assembled in vitro with microfabrication techniques. Microfabricated vessels, commonly referred to as "vessels-on-a-chip," are from a class of cell culture technologies that uniquely integrate microscale flow phenomena, tissue-level biomolecular transport, cell-cell interactions, and proper three-dimensional (3-D) extracellular matrix environments under well-defined culture conditions. Here, we discuss the enabling attributes of microfabricated vessels that make these models more physiological compared with established cell culture techniques and the potential of these models for advancing microvascular research. This review highlights the key features of microvascular transport and physiology, critically discusses the strengths and limitations of different microfabrication strategies for studying the microvasculature, and provides a perspective on current challenges and future opportunities for vessel-on-a-chip models.

Periosteal new bone formation in Klippel-Trénaunay syndrome: a case report

BACKGROUND

Klippel-Trénaunay syndrome (KTS) is a complex congenital vascular disorder, typically accompanied by port-wine stains, varicose veins, and limb hypertrophy. This paper reports a rare and unusual clinical condition of periosteal reaction in a pediatric case of KTS. Although periosteal new bone formation is not rare in children, as is KTS, their dual occurrence or the presentation of the former due to KTS has not been previously documented. Our objective in this study is to highlight the potential association between periosteal new bone formation and KTS, as well as to help physicians consider this association when bone neoplasm has been ruled out.

CASE PRESENTATION

A 7-year old girl, initially presented with a persistent mild swelling in her left shank, with no abnormalities in the X-ray of the tibiofibular. However, after a few consults and examinations, 7 weeks later, a 17 cm-long periosteal new bone formation along the left tibia and diffused dilated vessels in the left shank were revealed by the radiological examination. Not knowing the true nature of the fast-growing lesion in a typical case of KTS was worrying. Therefore, a core needle biopsy was performed. The test demonstrated a possible parosteal hemangioma. Following further investigation through an excisional biopsy, and a pathological analysis, hyperplasia of the bone tissues with no tumor cells was revealed. Thereafter, an elastic stocking treatment was prescribed. During the first two-year follow-up, recurrence of the mass or sign of progression of KTS was not observed.

CONCLUSIONS

Periosteal new bone formation is a potential manifestation of KTS. Based on the conclusive pathological results of the excisional biopsy, invasive examinations and surgeries could be avoided in future KTS-subperiosteal lesion manifestations.

Klippel-Trenaunay-Weber Syndrome Associated with Multiple Cerebral Arteriovenous Malformations: Usefulness of Gamma Knife Stereotactic Radiosurgery in This Syndrome

BACKGROUND

Klippel-Trenaunay-Weber syndrome (KTWS) is characterized by the presence of a combined vascular malformation of capillaries, veins, and lymphatic vessels; congenital venous abnormalities; and limb hypertrophy. Its association with neurovascular abnormalities is infrequent, and the presence of intracranial arteriovenous malformations (AVMs) is extremely rare.

CASE DESCRIPTION

We report a case of a 48-year-old male diagnosed with KTWS who spontaneously presented with a cerebral hemorrhage. Computed tomography scan and angio-computed tomography studies revealed bleeding associated with AVM rupture. In the conventional arteriography study, 10 small (<1 cm) AVMs were observed. The patient presented a good clinical recovery. These multiple small lesions were not considered susceptible to surgical or endovascular treatments. Therefore all lesions were treated with Gamma Knife stereotactic radiosurgery since it attains the highest dose drop and minimal irradiation of the healthy parenchyma. One year after the treatment, the lesions have shrunk.

CONCLUSIONS

Cerebral AVMs are extremely rare in KTWS cases; however, their presence can have serious consequences if they are treated. We find it advisable to include brain imaging tests, such as nuclear magnetic resonance imaging, to diagnose and monitor KTWS. Furthermore, a Gamma Knife may be useful when multiple AVMs are present.

Elevated expression of AGGF1 predicts poor prognosis and promotes the metastasis of colorectal cancer

Background

Angiogenic factor with G-patch and FHA domains 1 (AGGF1) can promote angiogenesis and increasing evidence has highlighted the important roles of AGGF1 in tumorigenesis. However, the differential expression as well as the biological functions of AGGF1 in colorectal cancer (CRC) remain to be established. The purpose of the present study is therefore to identify the effect of AGGF1 on prognosis and metastasis in CRC patients.

Methods

The expression level of AGGF1 in CRC was examined by qPCR, western blot and immunohistochemistry in a tissue microarray containing 236 CRC specimens and paired normal mucosae. And the effect of AGGF1 on CRC cell malignance was investigated in our established stable AGGF1 upregulated and knockdown CRC cell lines.

Results

The expression level of AGGF1 in CRC tissue was not significantly different to that in adjacent normal mucosa at the mRNA level. However, at the protein level, AGGF1 expression in CRC tissues was significantly higher than in paired normal mucosa, which showed a clear association with TNM stage, AJCC stage, vascular invasion, and differentiation. Further, we revealed an apparent correlation between AGGF1 expression and poorer disease-free survival and overall survival of CRC patients. In addition, we discovered that AGGF1 significantly promoted CRC cell wound healing, migration, and invasion in vitro and distant metastasis in vivo.

Conclusions

Our study demonstrates the aberrant overexpression of AGGF1 in CRC and provides a basis on which to explore the application of AGGF1 as a potential therapeutic target for CRC patients, especially for CRC patients with distant metastasis.

Cerebral Cavernous Angioma Associated with Klippel Trenaunay Syndrome Treated with Gamma Knife Radiosurgery: Case Report and Literature Review

Klippel Trenaunay syndrome (KTS) is a rare, sporadic congenital syndrome characterized by cutaneous hemangiomas, venous varicosities, and osseous-soft tissue hypertrophy of the affected limb. It is genetically heterogeneous, and its clinical presentation is variable.

We report the case of a 13-year-old male with KTS, who presented with a cerebral cavernous angioma in the corpus callosum. To the best of our knowledge, this is the first reported case of its kind from Pakistan and the only known case in the literature of KTS to be treated with stereotactic radiosurgery.

The possibilities of shared genetic pathways between KTS and cavernous angiomas and the need for neurovascular scrutiny in patients with this syndrome are discussed.

Cerebral and spinal cavernomas associated with Klippel-Trenaunay syndrome: case report and literature review

Klippel-Trenaunay-Weber syndrome (KTWS) involves a triad of conditions, including cutaneous hemangiomas, venous varicosities, and osseous and soft-tissue hypertrophy of the affected limb. We describe a rare case of multiple cavernomas in the central nervous system in a patient with KTWS. A-64-year-old man with KTWS and a previous brain hemorrhage presented with sudden onset of gait and vesicorectal disturbance. The magnetic resonance imaging scan showed a cavernoma associated with hemorrhage in his lumbosacral spinal cord. Moreover, numerous cavernomas were identified in his brain. He was treated conservatively with no adverse events. Gait disturbance improved, but vesicorectal disturbance did not improve.

The Effect of MCM3AP-AS1/miR-211/KLF5/AGGF1 Axis Regulating Glioblastoma Angiogenesis

Glioblastoma (GBM) is the most aggressive and malignant primary tumor. Angiogenesis plays a critical role in the progression of GBM. Previous studies have indicated that long non-coding RNAs (lncRNAs) are abnormally expressed in various cancers and participate in the regulation of the malignant behaviors of tumors. The present study demonstrated that lncRNA antisense 1 to Micro-chromosome maintenance protein 3-associated protein (MCM3AP-AS1) was upregulated whereas miR-211 was downregulated in glioma-associated endothelial cells (GECs). Knockdown of MCM3AP-AS1 suppressed the cell viability, migration, and tube formation of GECs and played a role in inhibiting angiogenesis of GBM in vitro. Furthermore, knockdown of MCM3AP-AS1 increased the expression of miR-211. Luciferase reporter assay implicated that miR-211 targeted KLF5 3'-UTR and consequently inhibited KLF5 expression. Besides, in this study we found that MCM3AP-AS1 knockdown decreased KLF5 and AGGF1 expression by upregulating miR-211. In addition, KLF5 was associated with the promoter region of AGGF1. Knockdown of KLF5 decreased AGGF1 expression by transcriptional repression, and also inhibited the activation of PI3K/AKT and ERK1/2 signaling pathways. Overall, this study reveals that MCM3AP-AS1/miR-211/KLF5/AGGF1 axis plays a prominent role in the regulation of GBM angiogenesis and also serves as new therapeutic target for the anti-angiogenic therapy of glioma.

Spinal Cavernous Angioma Associated with Klippel-Trenaunay-Weber Syndrome: Case Report and Literature Review

BACKGROUND

Klippel-Trenaunay-Weber syndrome (KTWS) is a rare congenital vascular disorder characterized by the classic triad of cutaneous nevi, venous varicosities, and osseous and soft tissue hypertrophy of the affected limb. Various vascular anomalies of the central nervous system have also been described in patients with KTWS. The English language literature to date contains 6 reports of associations between KTWS and spinal cord cavernous angioma (CA), but management of these patients has not been well described.

CASE DESCRIPTION

A 23-year-old woman was admitted to our institution with acute onset of leg weakness accompanied by upper back pain. Thoracic magnetic resonance imaging of the spinal cord showed a heterogeneous mass with a slit component at the T1-2 level. The patient underwent left hemilaminectomy followed by removal of the tumor, and her neurologic symptoms improved postoperatively. Pathologic examination showed the spinal lesion was characterized by hemosiderin deposition and thin-walled vascular channels surrounded by fibrous tissue.

CONCLUSIONS

This is the first report to provide a detailed pathologic description of the features of spinal CA in a patient with KTWS. Assessment of the clinical features and management of CA associated with KTWS are discussed. This syndrome is rare, and further experience in the treatment of these patients is needed. However, considering that the pathologic findings of spinal CA in patients with KTWS include the typical features of CA, the management of CA in patients with KTWS may be identical to management of isolated CA.

Haploinsufficiency of Klippel-Trenaunay syndrome gene Aggf1 inhibits developmental and pathological angiogenesis by inactivating PI3K and AKT and disrupts vascular integrity by activating VE-cadherin

Aggf1 is the first gene identified for Klippel-Trenaunay syndrome (KTS), and encodes an angiogenic factor. However, the in vivo roles of Aggf1 are incompletely defined. Here we demonstrate that Aggf1 is essential for both physiological angiogenesis and pathological tumour angiogenesis in vivo. Two lines of Aggf1 knockout (KO) mice showed a particularly severe phenotype as no homozygous embryos were observed and heterozygous mice also showed embryonic lethality (haploinsufficient lethality) observed only for Vegfa and Dll4. Aggf1+/- KO caused defective angiogenesis in yolk sacs and embryos. Survived adult heterozygous mice exhibit frequent haemorrhages and increased vascular permeability due to increased phosphorylation and reduced membrane localization of VE-cadherin. AGGF1 inhibits VE-cadherin phosphorylation, increases plasma membrane VE-cadherin in ECs and in mice, blocks vascular permeability induced by ischaemia-reperfusion (IR), restores depressed cardiac function and contraction, reduces infarct sizes, cardiac fibrosis and necrosis, haemorrhages, edema, and macrophage density associated with IR. Mechanistically, AGGF1 promotes angiogenesis by activating catalytic p110α subunit and p85α regulatory subunit of PI3K, leading to activation of AKT, GSK3β and p70S6K. AKT activation is significantly reduced in heterozygous KO mice and isolated KO ECs, which can be rescued by exogenous AGGF1. ECs from KO mice show reduced capillary angiogenesis, which is rescued by AGGF1 and AKT. Tumour growth/angiogenesis is reduced in heterozygous mice, which was associated with reduced activation of p110α, p85α and AKT. Together with recent identification of somatic mutations in p110α (encoded by PIK3CA), our data establish a potential mechanistic link between AGGF1 and PIK3CA, the two genes identified for KTS.

Targeting AGGF1 (angiogenic factor with G patch and FHA domains 1) for Blocking Neointimal Formation After Vascular Injury

Background

Despite recent improvements in angioplasty and placement of drug‐eluting stents in treatment of atherosclerosis, restenosis and in‐stent thrombosis impede treatment efficacy and cause numerous deaths. Research efforts are needed to identify new molecular targets for blocking restenosis. We aim to establish angiogenic factor AGGF1 (angiogenic factor with G patch and FHA domains 1) as a novel target for blocking neointimal formation and restenosis after vascular injury.

Methods and Results

AGGF1 shows strong expression in carotid arteries; however, its expression is markedly decreased in arteries after vascular injury. AGGF1^+/− mice show increased neointimal formation accompanied with increased proliferation of vascular smooth muscle cells (VSMCs) in carotid arteries after vascular injury. Importantly, AGGF1 protein therapy blocks neointimal formation after vascular injury by inhibiting the proliferation and promoting phenotypic switching of VSMCs to the contractile phenotype in mice in vivo. In vitro, AGGF1 significantly inhibits VSMCs proliferation and decreases the cell numbers at the S phase. AGGF1 also blocks platelet‐derived growth factor‐BB–induced proliferation, migration of VSMCs, increases expression of cyclin D, and decreases expression of p21 and p27. AGGF1 inhibits phenotypic switching of VSMCs to the synthetic phenotype by countering the inhibitory effect of platelet‐derived growth factor‐BB on SRF expression and the formation of the myocardin/SRF/CArG‐box complex involved in activation of VSMCs markers. Finally, we show that AGGF1 inhibits platelet‐derived growth factor‐BB–induced phosphorylation of MEK1/2, ERK1/2, and Elk phosphorylation involved in the phenotypic switching of VSMCs, and that overexpression of Elk abolishes the effect of AGGF1.

Conclusions

AGGF1 protein therapy is effective in blocking neointimal formation after vascular injury by regulating a novel AGGF1‐MEK1/2‐ERK1/2‐Elk‐myocardin‐SRF/p27 signaling pathway.

Neurocutaneous syndromes

Neurocutaneous syndromes (or phakomatoses) are a diverse group of congenital disorders that encompass abnormalities of neuroectodermal and, sometimes, mesodermal development, hence commonly involving the skin, eye, and central nervous system. These are often inherited conditions and typically present in early childhood or adolescence. Some of the abnormalities and clinical symptoms may, however, be progressive, and there is an increased risk of neoplastic formation in many of the syndromes. As a group, neurocutaneous syndromes are characterized by distinctive cutaneous stigmata and neurologic symptomology, the latter often representing the most devastating and debilitating features of these diseases. Many of these syndromes are markedly heterogeneous in nature as they affect many organ systems. Given the incurable nature of these conditions and the broad spectrum of pathologies they comprise, treatments vary on a case-by-case basis and tend to be palliative rather than curative. With the advances in molecular genetics, however, greater understanding of biologic functions of the gene products and the correlative phenotypic expression is being attained, and this knowledge may guide future therapeutic developments. This chapter focuses on the cutaneous and neurologic pathology with emphasis on neuroimaging of selective neurocutaneous syndromes, including tuberous sclerosis, Sturge-Weber syndrome, Klippel-Trenaunay syndrome, ataxia-telangiectasia, and incontinentia pigmenti.

Klippel-Trenaunay and Sturge-Weber overlapping syndrome in a Saudi boy

Sturge-Weber Syndrome (SWS) is a rare, sporadic neurocutaneous disorder. It is typically characterized by unilateral, posterior leptomeningeal angiomas that calcify, glaucoma, and facial portwine tains. Klippel-Trenaunay syndrome (KTS) is a rare congenital syndrome characterized by ipsilateral cutaneous capillary malformations, venous varicosities, and bony or soft tissue overgrowth of the affected limbs. The clinical, neuroradiological features as well as the outcome of a Saudi boy who was referred to the Division of Pediatric Neurology, King Saud University Medical City, Riyadh, Saudi Arabia, with intractable focal seizure and left-sided hemiparesis who was eventually diagnosed with combined SWS and KTS is described here. The rare coexistence of SWS and KTS should be suspected in a child presenting with neurological manifestation such as epilepsy, mental sub normality, or hemiparesis, with port-wine staining or capillary hemangioma and enlarged limbs. Awareness may help in improving the quality of life and survival of these patients.

Deep Vein Thrombosis in Patients with Severe Motor and Intellectual Disabilities, Especially Diagnosis and Prevention of Recurrence for Chronic Thrombosis-Serial Changes of Sonography and D-Dimer

Most patients with severe motor and intellectual disabilities (SMID) have restricted mobility capability and have been bedridden for long periods because of paralysis of the extremities caused by abnormal muscular tonicity due to cerebral palsy and developmental disabilities. Such patients are associated with a high risk of complications like deep vein thrombosis (DVT). Here, we report twelve patients (42.9%) with DVT among 28 patients with SMID during prolonged bed rest. However, we did not detect thrombosis in the soleal veins, finding it mostly in the femoral and common femoral veins. We applied anticoagulant therapy (warfarin), and carefully followed up the cases with DVT, regulating the warfarin dosage at prothrombin time-international normalized ratio (PT-INR) values around two to prevent recurrence of chronic thrombosis. Regarding laboratory data for the coagulation system, there were no cases above 5 µg/ml for the D-dimer and there were significant differences between the DVT and non-DVT groups in the D-dimer levels. The plasma levels of D-dimer in patients with DVT diminished to less than 1.0 µg/ml after warfarin treatment. Concerning sudden death (4.2%) in patients with SMID, we have to be very careful of the possibility of pulmonary thromboembolism due to DVT. Therefore, we should consider the particularity of the underdeveloped vascular system from underlying diseases for the evaluation of DVT. A detailed study of DVT as a vascular complication is very important for the smooth medical care of SMID, and serial assessment of compression Doppler ultrasonography of the lower extremities, as a noninvasive examination and measurement of D-dimer, is very helpful. (This article is a translation of Jpn J Phlebol 2014; 25: 34-42.).

A rare case of unilateral variations of forearm arteries: anatomy, embryology and clinical implications

This study documents the existence and topographic anatomy of a rare case of variant forearm arteries found in the left upper limb of a 68-year-old male cadaver. The arteries of the arm followed typical courses, but both the radial and ulnar arteries in the forearm followed a superficial course. The common interosseous artery and recurrent ulnar arteries branched from the radial, not the ulnar, artery. The radial artery was larger than the ulnar artery and was the major source of blood supply to the forearm. Clinical implications for single superficial forearm arteries are reviewed. A person with both superficial radial and superficial ulnar arteries would be at a substantially increased risk of injury or iatrogenic effects that could compromise blood supply to the hand. This study will enhance clinician's awareness of potential arterial variations, so they can provide adequate assessment, diagnosis and treatment of upper limb lesions.

Deep vein thrombosis in patients with severe motor and intellectual disabilities

Most patients with severe motor and intellectual disabilities (SMID) have restricted mobility capability and have been bedridden for long periods because of paralysis of the extremities caused by abnormal muscular tonicity due to cerebral palsy and developmental disabilities, and such patients are associated with a high risk for the complications of deep vein thrombosis (DVT). Here, we report 8 patients (34.8%) with DVT among 23 patients with SMID during prolonged bed rest. However, we did not detect thrombosis in the soleal veins, finding it mostly in the superficial femoral and common femoral veins. Regarding laboratory data for the coagulation system, there were no cases with D-dimer above 5 µg/ml. Concerning sudden death in patients with SMID, we have to be very careful of the possibility of pulmonary thromboembolism due to DVT. Therefore, we should consider the particularities of an underdeveloped vascular system from underlying diseases for the evaluation of DVT in patients with SMID. A detailed study of DVT as a vascular complication is very important for smooth medical care of SMID and compression Doppler ultrasonography of the lower extremities, as noninvasive examination, is very helpful. (English translation of Jpn J Phlebol 2012; 23: 17-24).

Intraosseous arteriovenous malformation of the sphenoid bone presenting with orbital symptoms mimicking cavernous sinus dural arteriovenous fistula: a case report

Intraosseous arteriovenous malformation (AVM) in the craniofacial region is rare. When it occurs, it is predominantly located in the mandible and maxilla. We encountered a 43-year-old woman with Klippel-Trenaunay syndrome affecting the right lower extremity who presented with a left orbital chemosis and proptosis mimicking the cavernous sinus dural arteriovenous fistula. Computed tomography angiography revealed an intraosseous AVM of the sphenoid bone. The patient's symptoms were completely relieved after embolization with Onyx. We report an extremely rare case of intraosseous AVM involving the sphenoid bone, associated with Klippel-Trenaunay syndrome.

Lethal outcomes in Klippel-Trenaunay syndrome

Klippel-Trenaunay syndrome (KTS) is an uncommon congenital angiodysplasia that manifests in infancy and is characterized by venous and lymphatic malformations of the skin, soft tissue, and bone causing limb hypertrophy. We report 2 patients with long-term KTS who developed lethal complications from uncommon and unusual manifestations. The 1st patient was a female with KTS who at 2 years of age underwent a below-the-knee amputation for a massively hypertrophied and malformed left foot. Two years later she required additional surgical removal of vascular malformations involving her left calf with extension to the groin, pubis, and ipsilateral abdomen. Fifteen years later she underwent splenectomy (400 g) revealing multifocal, cystically dilated vascular channels distorting the splenic architecture and died suddenly of massive intra-abdominal hemorrhage on the 2nd postoperative day. The 2nd patient was a 72-year-old male with long-standing KTS who presented with debilitating chronic penile and scrotal edema. Surgical excision of his lymphedematous scrotal and penile skin revealed a low-grade angiosarcoma arising in the setting of chronic lymphedema. The patient died shortly after surgery from massive hemorrhage due to traumatic rupture of malformed leg vessels. KTS may lead to significant morbidity and mortality, and pathologic consequences from long-term KTS have been rarely reported. These cases illustrate the risk of lethal hemorrhage, organomegaly from protracted vascular malformation, and development of vascular neoplasia associated with chronic lymphedema in KTS.

Nevus vascularis mixtus (cutaneous vascular twin nevi) associated with intracranial vascular malformation of the Dyke-Davidoff-Masson type in two patients

The term twin spotting refers to phenotypes characterized by the spatial and temporal co-occurrence of two (or more) different nevi arranged in variable cutaneous patterns, and can be associated with extra-cutaneous anomalies. Several examples of twin spotting have been described in humans including nevus vascularis mixtus, cutis tricolor, lesions of overgrowth, and deficient growth in Proteus and Elattoproteus syndromes, epidermolytic hyperkeratosis of Brocq, and the so-called phacomatoses pigmentovascularis and pigmentokeratotica. We report on a 28-year-old man and a 15-year-old girl, who presented with a previously unrecognized association of paired cutaneous vascular nevi of the telangiectaticus and anemicus types (naevus vascularis mixtus) distributed in a mosaic pattern on the face (in both patients) and over the entire body (in the man) and a complex brain malformation (in both patients) consisting of cerebral hemiatrophy, hypoplasia of the cerebral vessels and homolateral hypertrophy of the skull and sinuses (known as Dyke-Davidoff-Masson malformation). Both patients had facial asymmetry and the young man had facial dysmorphism, seizures with EEG anomalies, hemiplegia, insulin-dependent diabetes mellitus (IDDM), autoimmune thyroiditis, a large hepatic cavernous vascular malformation, and left Legg-Calvé-Perthes disease (LCPD) [LCPD-like presentation]. Array-CGH analysis and mutation analysis of the RASA1 gene were normal in both patients.

Angiogenic factor AGGF1 promotes therapeutic angiogenesis in a mouse limb ischemia model

BACKGROUND

Peripheral arterial disease (PAD) is a common disease accounting for about 12% of the adult population, and causes significant morbidity and mortality. Therapeutic angiogenesis using angiogenic factors has been considered to be a potential treatment option for PAD patients. In this study, we assessed the potential of a new angiogenic factor AGGF1 for therapeutic angiogenesis in a critical limb ischemia model in mice for PAD.

METHODS AND RESULTS

We generated a unilateral hindlimb ischemia model in mice by ligation of the right common iliac artery and femoral artery. Ischemic mice with intrasmuscular administration of DNA for an expression plasmid for human AGGF1 (AGGF1 group) resulted in increased expression of both AGGF1 mRNA and protein after the administration compared with control mice with injection of the empty vector (control group). Color PW Doppler echocardiography showed that the blood flow in ischemic hindlimbs was significantly increased in the AGGF1 group compared to control mice at time points of 7, 14, and 28 days after DNA administration (n = 9/group, P = 0.049, 0.001, and 0.001, respectively). Increased blood flow in the AGGF1 group was correlated to increased density of CD31-positive vessels and decreased necrosis in muscle tissues injected with AGGF1 DNA compared with the control tissue injected with the empty vector. Ambulatory impairment was significantly reduced in the AGGF1 group compared to the control group (P = 0.004). The effect of AGGF1 was dose-dependent. At day 28 after gene transfer, AGGF1 was significantly better in increasing blood flow than FGF-2 (P = 0.034), although no difference was found for tissue necrosis and ambulatory impairment.

CONCLUSIONS

These data establish AGGF1 as a candidate therapeutic agent for therapeutic angiogenesis to treat PAD.

Overlap of sturge-weber syndrome and klippel-trenaunay syndrome

Sturge–Weber syndrome is a rare sporadic condition of mesodermal phakomatosis, characterized by purple-colored flat cutaneous cranial (face) hemangiomas (most commonly along the trigeminal nerve), glaucoma and vascular lesions in the ipsilateral brain and meninges. Klippel–Trenaunay syndrome is also an uncommon mesodermal phakomatosis characterized by a triad of cutaneous and visceral hemangiomas, venous varicosities and soft tissue or bone hypertrophy. Sturge–Weber syndrome in combination with Klippel–Trenaunay syndrome is unusual. Because of the rarity, we report here a 3-year-old boy who presented with overlapping features of both the syndromes.

Vascular and perivascular lesions of skin and soft tissues in children and adolescents

Vascular anomalies in children and adolescents are the most common soft tissue lesions and include reactive, malformative, and neoplastic tumefactions, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic complexity and recent changes in classification systems, some of which are based on clinical features and others on pathologic findings. In recent decades, there have been significant advances in clinical diagnosis, development of new therapies, and a better understanding of the genetic aspects of vascular biology and syndromes that include unusual vascular proliferations. Most vascular lesions in children and adolescents are benign, although the intermediate locally aggressive and intermediate rarely metastasizing neoplasms are important to distinguish from benign and malignant mimics. Morphologic recognition of a vasoproliferative lesion is straightforward in most instances, and conventional morphology remains the cornerstone for a specific diagnosis. However, pathologic examination is enhanced by adjunctive techniques, especially immunohistochemistry to characterize the type of vessels involved. Multifocality may cause some uncertainty regarding the assignment of "benign" or "malignant." However, increased interest in vascular anomalies, clinical expertise, and imaging technology have contributed greatly to our understanding of these disorders to the extent that in most vascular malformations and in many tumors, a diagnosis is made clinically and biopsy is not required for diagnosis. The importance of close collaboration between the clinical team and the pathologist cannot be overemphasized. For some lesions, a diagnosis is not possible from evaluation of histopathology alone, and in a subset of these, a specific diagnosis may not be possible even after all assembled data have been reviewed. In such instances, a consensus diagnosis in conjunction with clinical colleagues guides therapy. The purpose of this review is to delineate the clinicopathologic features of vascular lesions in children and adolescents with an emphasis on their unique aspects, use of diagnostic adjuncts, and differential diagnosis.

Dominant inheritance and intra-familial variations in the association of Sturge-Weber and Klippel-Trenaunay-Weber syndromes

This case report shows a genealogical study where a woman has limb hypertrophy and her son has an association of Sturge–Weber syndrome with Klippel–Trenaunay–Weber syndrome. The Sturge–Weber and Klippel–Trenaunay–Weber syndromes appear to be different manifestations of the same affliction. Familial aggregation exists and transmission may be almost imperceptible between generations. Identification of minor manifestations may prove to be a valuable contribution to genetic counseling of families and the prevention of new cases.

Pediatric Vascular Tumors and Malformations

Pediatric vascular tumors and malformations, comprising a broad category of lesions often referred to as vascular anomalies, are a heterogenous group of clinicopathologically distinct entities. Pathologists, clinicians, and radiologists have traditionally lumped these lesions under the generic term, hemangioma, sometimes qualified by modifiers, such as capillary or cavernous. Advances in understanding underlying pathogenetic mechanisms support more specific classification and more specifically targeted therapies. Multidisciplinary consensus has moved toward a biologically based classification system and therapeutic approach for dealing with these lesions. This content focuses on the histologic, immunophenotypical, and clinical features that distinguish the major types of vascular tumors and malformations presenting in infancy and childhood. Pathogenic mechanisms are also briefly reviewed.

Recent progress in studies of infantile hemangioma

A hallmark of infantile hemangioma, the most common tumor of infancy, is its dramatic growth after birth, by diffuse proliferation of immature endothelial cells, followed by spontaneous regression. The growth and involution of infantile hemangioma is quite different from other vascular anomalies, which do not regress and can occur at any time during life. Some hemangioma lesions can be extremely disfiguring and destructive to normal tissue and may even be life-threatening. Unfortunately, existing therapeutic approaches have limited success and significant adverse effects of some treatment modalities limit their use. Better understanding of the pathogenesis of hemangioma will enable the development of better therapeutic strategies. Here, we review recent studies and new hypotheses on the pathogenesis of the tumor. Detailed mechanisms of activated vascular endothelial growth factor signaling in tumor cells, identification of their origin and characterization of multipotent stem cells that can give rise to infantile hemangioma are shedding new light on this intriguing vascular tumor.

Klippel-Trenaunay syndrome and spinal arteriovenous malformations: an erroneous association

BACKGROUND AND PURPOSE

KTS is a rare limb overgrowth disorder with slow-flow vascular anomalies. This study examines the presumed association between KTS and spinal AVMs.

MATERIALS AND METHODS

We performed a MEDLINE search of articles and reviewed textbooks of spinal diseases to study the association between KTS and spinal AVM. Our goal was to ascertain the basis on which the diagnosis of KTS was established and to evaluate the evidence of its association with spinal AVMs. In addition, the data base of the Vascular Anomalies Center at Children's Hospital Boston was queried for patients with KTS, and the association with spinal AVM was investigated.

RESULTS

Twenty-four published reports on spinal AVMs in 31 patients with KTS were reviewed. None of these references provided solid evidence of the diagnosis of KTS in any patient. Clinical data were either incompatible with the diagnosis of KTS or were inadequate to establish the diagnosis. Alternative possible diagnoses (CLOVES syndrome and CM-AVM) were suggested by the first author for 9 of the patients reported in these articles. The medical records of 208 patients with the diagnosis of KTS were analyzed; not a single patient had clinical or radiologic evidence of a spinal AVM.

CONCLUSIONS

An association between KTS and spinal AVM, as posited in numerous references, is most likely erroneous. The association has neither been reliably proved in the limited published literature nor encountered in a large cohort.

Intracranial aneurysms in klippel-trenaunay/weber syndromes: case report

OBJECTIVE

We present a comprehensive review of intracranial aneurysms in Klippel-Trenaunay and Klippel-Trenaunay-Weber syndromes (KTS/KTWS), and examine factors influencing the risks of surgery vs conservative management.

CLINICAL PRESENTATION

A 58-year-old physician with KTS affecting the right extremities presented with left hemispheric cerebellar stroke and was discovered to harbor four intracranial aneurysms of the posterior circulation: fusiform mid and distal BA (2.6 x 2 x 2 cm), fusiform right proximal P1 (2 x 1.3 x 1.3 cm), fusiform right distal P1 (2.8 x 2.7 x 2 cm), and saccular left distal posterior inferior cerebellar artery (2.5 x 2.5 x 2.5 cm). Ten years later he had an infarct in the paramedian distribution of the basilar artery and a right internal capsule stroke. Two months later, he developed hydrocephalus, ultimately presenting in status epilepticus 4 months later secondary to ongoing aneurysm expansion and mass effect.

INTERVENTION

Systemic anticoagulation for acute thrombosis with possible distal arterioarterial embolization from giant P1 aneurysms. Ventriculoperitoneal shunting for hydrocephalus. The patient died within 9 days after admission and 10 years after the initial discovery of aneurysms.

CONCLUSION

Strict control of modifiable risk factors compromising vascular integrity and periodic neuroimaging are warranted in KTS/KTWS patients. KTS/KTWS patients are hypercoagulable, and may be predisposed to aneurysm thrombosis with increased risk for distal arterial microembolization. Stroke-related morbidity secondary to distal arterioarterial aneurysm thrombus embolization and acute aneurysm thrombosis may be decreased with systemic anticoagulation in this patient population. KTS/KTWS patients have significantly higher rates of DVT and PE than the general population, and should be classified in the high-risk category for venous thromboembolism prophylaxis. Both endovascular and open cerebrovascular techniques have been used successfully in KTS/KTWS patients with intracranial aneurysms.

Open-bite orthodontic-surgical treatment in the Klippel-Trenaunay-Weber syndrome: a case report

We describe the orthodontic treatment of a patient with Klippel-Trenaunay-Weber syndrome (KTWS) who received orthodontic treatment that included rapid palatal expansion and orthognathic surgery. There is no report in the literature with this orthodontic treatment protocol, that was considered successful. The pros and cons of this approach as well as the risks involved are discussed.

The imaging of the cerebral venous sinuses

The cerebral venous sinuses in the past have been relatively neglected during radiological, neurological, and neurosurgical scientific discourse. However modern imaging and radiological approaches to treatment are demonstrating that far from being rare, the cerebral venous sinuses are involved in the pathogenesis of a protean list of ailments. During the review we hope to illustrate the imaging of diseases of the cerebral venous sinuses as demonstrated on multislice computer tomography and magnetic resonance imaging.