Rat Model of Parkes Weber Syndrome

RESEARCH ARTICLE Rat Model of Parkes Weber Syndrome Krzysztof Bojakowski1,2, Gabriela Janusz1, Iwona Grabowska3, Oliwia Zegrocka-Stendel1, Agnieszka Surowiecka-Pastewka1, Magdalena Kowalewska1,4, Dorota Maciejko1, Katarzyna Koziak1* 1 Department of Immunology, Biochemistry and Nutrition, Medical University of Warsaw, Warsaw, Poland, 2 Department of Internal Medicine, Hypertension and Vascular Diseases, Medical University of Warsaw, Warsaw, Poland, 3 Department of Cytology, Faculty of Biology, University of Warsaw, Warsaw, Poland, 4 Department of Molecular and Translational Oncology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland * Abstract OPEN ACCESS Citation: Bojakowski K, Janusz G, Grabowska I, Zegrocka-Stendel O, Surowiecka-Pastewka A, Kowalewska M, et al. (2015) Rat Model of Parkes Weber Syndrome. PLoS ONE 10(7): e0133752. doi:10.1371/journal.pone.0133752 Editor: Stephen L. Clarke, Oklahoma State University, UNITED STATES Received: February 3, 2015 Accepted: July 1, 2015 Published: July 28, 2015 Copyright: © 2015 Bojakowski et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The Parkes Weber syndrome is a congenital vascular malformation, characterized by varicose veins, arterio-venous fistulas and overgrown limbs. No broadly accepted animal model of Parkes Weber syndrome has been described. We created side-to-side arteriovenous fistula between common femoral vessels with proximal non-absorbable ligature on common femoral vein limiting the enlargement of the vein diameter in Wistar rats. Contralateral limb was sham operated. Invasive blood pressure measurements in both iliac and inferior cava veins were performed in rats 30 days after fistula creation. Tight circumference and femoral bone length were measured. Histopathology and morphology of soleus muscle, extensor digitorum longus muscle, and the common femoral vessel were analyzed. 30 days following arterio-venous fistula creation, a statistically significant elevation of blood pressure in common iliac vein and limb overgrowth was observed. Limb enlargement was caused by muscle overgrowth, varicose veins formation and bone elongation. Arteriovenous fistula with proximal outflow limitation led to significant increase of femoral vein circumference and venous wall thickness. Our study indicates that the described rat model mimics major clinical features characteristic for the human Parkes Weber syndrome: presence of arterio-venous fistula, venous hypertension and dilatation, varicose veins formation, and the limb hypertrophy. We reveal that limb overgrowth is caused by bone elongation, muscle hypertrophy, and venous dilatation. The newly established model will permit detailed studies on the mechanisms underlying the disease and on the efficacy of novel therapeutic strategies for the Parkes Weber syndrome treatment. Data Availability Statement: All relevant data are within the paper. Funding: This work was supported by the European Union Operational Program “Innovative Economy” grant No. POIG.01.01.02-14-072/09. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. Introduction The Parkes Weber syndrome (PWS), first described in 1907 [1], is characterized by a triad of arteriovenous fistulas (AVF), varicose veins and bone and soft tissue hypertrophy leading to limb enlargement. The presence of AVF distinguishes PWS from the Klippel-Trenaunay syndrome, known also as the capillary-lymphatic-venous malformation, CLVM [2]. The PLOS ONE | DOI:10.1371/journal.pone.0133752 July 28, 2015 1 / 12 Rat Model of Parkes Weber Syndrome symptoms of PWS are congenital and present at birth. Most cases of PWS are sporadic, although familial histories have been reported. Vascular anomalies usually affect a limb, most commonly a leg, and less often a trunk. Capillary malformations, forming geographic patterns, are typically located on lateral side of the limb, buttocks or trunk. The appearance of varicose veins and dilated superficial veins in older age is triggered by arteriovenous shunt, venous hypertension and insufficiency of the deep venous system. The enlargement of a limb is present at birth, and the axial overgrowth can enlarge in postnatal period [3, 4]. Cases of shortened lower extremity and pelvis malformations have also been described [5]. Arteriovenous shunt may also lead to cardiac system failure or to limb ischemia. Not surprisingly, PWS, similarly to other vascular malformations, significantly reduces the quality of life of the affected patients [6]. Diagnosis of PWS is mostly based on color Doppler ultrasound, computer tomography, magnetic resonance imaging and rarely on arteriography all of which permit to detect and characterize vascular malformations such as AVF. The treatment of patients with PWS is mainly symptomatic. Compression therapy is used to reduce symptoms of chronic venous insufficiency and lymphatic edema. In selected cases invasive procedures are performed. Surgical treatment is difficult and may require several intravascular procedures, such as embolization, sclerotherapy or classic open operations involving arteriovenous fistula ligation. In severe cases of ischemic extremities amputation is the only therapy. It has been documented that in a majority of PWS patients vascular malformations result from loss-of-function mutations in the RASA1 gene encoding p120 Ras GTPase-activating protein [7, 8]. Although there has been no mechanistic explanation of how the mutations of a globally expressed gene specifically affect vasculature, a recent work suggests that deregulation of EPHB4/RASA1/mTORC1 signaling in endothelial cells caused by insufficient RAS inactivation could disrupt the process of arteriovenous differentiation, creating malformations in capillaries, arteries and veins [9]. In addition, there is at least one documented case of PWS patient demonstrating lymphatic abnormalities probably resulting from mispatterning of peripheral and mesenteric lymphatics and insufficiency of hypertrophic lymphatic channels [7]. This remains in concordance with data obtained from RASA1-knock-out mice which exhibited hyperplasia of the initial lymphatics as well as dilation of initial and collecting lymphatic vessels [7]. To date, no animal model reproducing complex manifestations of PWS and applicable for research on etiology, treatment and prevention of the disease, has been developed. The only attempt reported to date in mammals was generation of Rasa1-deficient mice [10]. Such animals develop lymphatic malformations which are also observed in PWS patients, but other abnormalities characteristic for the disease, e.g. vein a (...truncated)