Background:Mastocytosis is a heterogeneous group of disorders characterized by abnormal accumulation of mast cells. Objective: Skin biopsies from 24 patients (23 with proven mastocytosis) were screened for the presence of the c-kit Asp-816-Val mutation. Methods: In frozen biopsies, RNA was isolated, cDNA synthesis and PCR, the expected PCR product of 346 bp was obtained from 23 patients. Results:In patients with urticaria pigmentosa, the mutation was detected in 38% of the adults and 25% of the children. With regard to the clinical presentation of the disease, no difference was found between adult patients with and without the mutation, as detected with our assay. One out of the 2 children with the mutation had an atypical presentation of the disease. Conclusion: the mutation could not be detected in all the patients, probably due to lack of sensitivity of the methods.

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study. Video LinkThe video component of this article can be found at

Prematurely born young adults who experienced neonatal oxidative injury (NOI) of the lungs have increased incidence of cardiovascular disease. Here, we investigated the long‐term effects of NOI on cardiopulmonary function in piglets at the age of 10–12 weeks. To induce NOI, term‐born piglets (1.81 ± 0.06 kg) were exposed to hypoxia (10–12% FiO2${F}_{{\rm{iO}}_{\rm{2}}}$), within 2 days after birth, and maintained for 4 weeks or until symptoms of heart failure developed (range 16–28 days), while SHAM piglets were normoxia raised. Following recovery (>5 weeks), NOI piglets were surgically instrumented to measure haemodynamics during hypoxic challenge testing (HCT) and exercise with modulation of the nitric‐oxide system. During exercise, NOI piglets showed a normal increase in cardiac index, but an exaggerated increase in pulmonary artery pressure and a blunted increase in left atrial pressure – suggesting left atrial under‐filling – consistent with an elevated pulmonary vascular resistance (PVR), which correlated with the duration of hypoxia exposure. Moreover, hypoxia duration correlated inversely with stroke volume (SV) during exercise. Nitric oxide synthase inhibition and HCT resulted in an exaggerated increase in PVR, while the PVR reduction by phosphodiesterase‐5 inhibition was enhanced in NOI compared to SHAM piglets. Finally, within the NOI piglet group, prolonged duration of hypoxia was associated with a better maintenance of SV during HCT, likely due to the increase in RV mass. In conclusion, duration of neonatal hypoxia appears an important determinant of alterations in cardiopulmonary function that persist further into life. These changes encompass both pulmonary vascular and cardiac responses to hypoxia and exercise. Key points Children who suffered from neonatal oxidative injury, such as very preterm born infants, have increased risk of cardiopulmonary disease later in life. Risk stratification requires knowledge of the mechanistic underpinning and the time course of progression into cardiopulmonary disease. Exercise and hypoxic challenge testing showed that 10‐ to 12‐week‐old swine that previously experienced neonatal oxidative injury had increased pulmonary vascular resistance and nitric oxide dependency. Duration of neonatal oxidative injury was a determinant of structural and functional cardiopulmonary remodelling later in life. Remodelling of the right ventricle, as a result of prolonged neonatal oxidative injury, resulted in worse performance during exercise, but enabled better performance during the hypoxic challenge test. Increased nitric oxide dependency together with age‐ or comorbidity‐related endothelial dysfunction may contribute to predisposition to pulmonary hypertension later in life.

IntroductionFollowing myocardial infarction (MI), left ventricular (LV) remodeling aims to maintain cardiac function. Nevertheless, adverse remodeling results in thinning of the infarct and LV dilation which may subsequently lead to the development of heart failure (HF) with poor prognosis. Wnt/Frizzled signaling plays a key role in cardiac remodeling following MI. We have shown previously that blockade of Wnt/Frizzled signaling with UM206 suppresses adverse remodeling and prevents HF development in mice post‐MI. Here we investigated the effects of UM206 therapy in a clinically relevant large animal model.MethodsTwelve Yorkshire x Landrace swine were subjected to 2h of myocardial ischemia by ligation of the proximal left circumflex artery, followed by reperfusion. Starting 24h post‐MI, 6 animals were treated with UM206 (0.6 μg/kg/day i.v.) for 5 weeks. The 6 control swine were treated with vehicle. Cardiac dimensions and infarct mass (IM) were determined by echocardiography and dedicated markers, respectively.ResultsTreatment with UM206 for 5 weeks resulted in a significant decrease in IM compared to baseline, whereas IM remained unaffected in the control group. This was accompanied by progressive dilation of the LV in the control group between 3 and 5 weeks after MI while adverse remodeling was halted in the UM206 treated group.ConclusionUM206 treatment in a clinically relevant swine model of reperfused myocardial infarction attenuates adverse remodeling.Supported by the Dutch Heart Foundation (2010B196)

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Introduction Advances in neonatal care improved the survival of very prematurely born infants. Exposure to high oxygen is often necessary to ensure adequate oxygen uptake in these infants, leading to halted development and oxidative injury of the pulmonary vasculature which is often accompanied by increased pulmonary arterial pressure (PAP). Although pressures normalize in school age childhood, various stressors as hypoxia and exercise may unmask increased pulmonary vasoreactivity. Furthermore, now that these infants reach adulthood, it is increasingly recognized that this large, preterm born adult cohort has a less favorable cardiopulmonary risk profile. Particularly male subjects were shown to respond with a higher increase in PAP upon re‐exposure to hypoxia, which might be a predisposition to pulmonary vascular disease later in life. Pathophysiological risk factors causing this predisposition are unidentified and challenging to investigate in the human population. Objective To assess if swine with perinatal oxidative injury of the pulmonary vasculature respond differently to re‐exposure to a hypoxic stimulus compared to healthy swine. Methods 6 male swine were exposed to 10–12% hypoxia in the neonatal period (NH‐swine) for a maximum of 4 weeks to interfere with normal lung development, while 5 male control pigs (healthy swine) were raised in normoxic conditions. In the NH‐swine, a symptom‐guided method (echocardiographic changes and clinical symptoms) orchestrated timing of the return to normoxic conditions. At the age of 8 weeks, NH and healthy swine were chronically instrumented. In week 10, hemodynamics were evaluated at rest and during exposure to 14–15% oxygen for 20 minutes. Results NH‐swine were exposed to a 23±5 days of hypoxia. 2 NH‐swine passed away as a consequence of heart failure before chronic instrumentation. At the age of 10 weeks, baseline PAP (14.6±2 vs 13.8±1 mmHg) and pulmonary vascular resistance (PVR, 4.1±0.7 vs 2.8±0.4 WU) at rest was not different in NH‐swine compared to healthy swine. During the hypoxic challenge, oxygen saturation decreased similarly in both groups compared to baseline measurements. PAP increased upon exposure to hypoxia due to an increase in PVR. The increases in PAP and PVR showed a transient peak after two minutes, which were larger in in NH‐swine compared to healthy swine. PAP and ΔPVR stabilized between 10 and 20 minutes of hypoxia exposure at levels that were not different between groups. Conclusions Interfering with normal lung development in the first weeks of life induces a transiently exaggerated increase in PAP and PVR during a hypoxic challenge at the age of ten weeks. Normalization of PAP and PVR suggests effective counter mechanisms to reduce cardiac work and increase arterial oxygen saturation. The increased response to hypoxia of the pulmonary circulation suggest long‐term structural and/or functional changes that possibly predisposes the pulmonary circulation to adult pulmonary vascular disease. Support or Funding Information ErasmusMC M‐RACE Hypox...

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Chronic Thromboembolic Pulmonary hypertension (CTEPH) is a deadly disease initiated by thrombo‐embolisms persisting in the pulmonary vasculature, followed by remodelling of the pulmonary vascular bed, resulting in a sustained increase in afterload of the right ventricle (RV). Although the response of the pulmonary vasculature to the initiating thromboembolic events as well as the response of the RV to the increased afterload are known to be the most important determinants of patient outcome, the factors that underlie these processes are incompletely understood. In the present study, we developed a novel chronically instrumented swine model of CTEPH. CTEPH was induced by up to 5 weekly injections of polyethylene beads of 700 μm in combination with induction of endothelial dysfunction by eNOS‐inhibition. Swine were followed up to one month after the last embolization. Changes in mean pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) were used as indices of RV afterload and pulmonary vascular remodeling. and assessed at rest and during treadmill exercise (EX) . Repeated embolization resulted in increases in PAP and PVR. Control After first embolization Prior to sacrifice rest EX rest Ex Rest Ex PAP (mmHg) 16±1 33±3* 29±3† 61±7*† 47±15† 72±16*† PVR (mmHg.min.kg.L‐1) 86±13 98±16 160±42† 197±23† 510±237† 633±344† * P<0.05 vs Rest, † P< 0.05 vs Control The increase in PAP was exaggerated during exercise, and in two animals, limited the increase in cardiac output during exercise. The increase in PVR induced by repeated embolization correlated well with RV weight (r2=0.78), indicating that swine developed RV hypertrophy. Moreover, histology revealed increased muscularization of pulmonary arterioles.In conclusion, our new swine model of CTEPH mimics critical features of patients with CTEPH in that pulmonary vascular remodeling is present and exercise capacity is reduced.Supported by CVON‐ PHAEDRA2012‐08