Effect of inhibition of Notch signal on pulmonary vascular remodeling induced by angiotensin Ⅱ / 中国当代儿科杂志

<p><b>OBJECTIVE</b>It is known that Notch signal is very important to vascular remodeling during the process of embryonic development, vessel repair and tumor growth, but there are few studies about pulmonary vascular remodeling in pulmonary hypertension. This study was to explore the effect of inhibiting Notch signal on pulmonary vascular remodeling induced by angiotensin II.</p><p><b>METHODS</b>Vessel strips taken from healthy Wistar rats were co-cultured with extrogenous angiotensin II and the potent smooth muscle cell proliferation stimulators for 7 days. Vascular wall thickness, proliferating cell nuclear antigen (PCNA) positive cell rate and caspase-3 positive cell rate were examined in vessel strips. Then some vessel strips were cultured with angiotensin II and γ-secretase inhibitor DAPT, a Notch signaling inhibitor for 7 days. The levels of Notch 1 to 4 receptor and HERP1/2 mRNA were ascertained by FQ-PCR.</p><p><b>RESULTS</b>Angiotensin II stimulation in the cultured normal pulmonary arteries resulted in an increase in the vascular medial thickness by nearly 50%, and a significant increase in the PCNA positive cell rate and a decrease in the caspase-3 positive cell rate. DAPT treatment did not result in the alterations of Notch 1 to 4 receptor levels, but decreased remarkably HERP1 and HERP2 mRNA expression. DAPT treatment also decreased angiotensin II-induced vascular medial thickness and PCNA positive cell rate and increased caspase-3 positive cell rate.</p><p><b>CONCLUSIONS</b>Inhibiting Notch signal by γ-secretase inhibitor may lead to the suppression of pulmonary vascular remodeling induced by angiotensin II, suggesting that the inhibition of Notch signal pathway might be a novel strategy for the treatment of pulmonary hypertension.</p>

Effect of doxycycline on the development of pulmonary hypertension induced by four methods in rats / 中华儿科杂志

<p><b>OBJECTIVE</b>Based on establishment of four rat models of experimental pulmonary hypertension (PH), the authors examined the inhibition of matrix metalloproteinases (MMPs) by doxycycline and its effect on the development of PH and associated pulmonary vascular remodeling.</p><p><b>METHOD</b>Healthy male Sprague-Dawley rats (weight 350 g to 400 g) were randomly divided into nine groups: Normal control group (N), four model groups (H, M, P, PM) and their corresponding drug intervention groups (HD, MD, PD, PMD) in which doxycycline was given by gavage at a 20 mg/kg daily dosage. On day 28 (day 35 for PM and PMD models), the animals were catheterized to record mean pulmonary arterial pressure (mPAP) and then sacrificed. Fulton Index [RV/(LV + S)] was measured immediately. Morphometric parameters, including percent vascular wall thickness and muscularization of non-muscularized peripheral pulmonary arterioles were determined microscopically. The activity of MMPs was measured by gelatin zymography in the lung tissue.</p><p><b>RESULTS</b>(1) Rats in all model groups (H, M, P, PM) developed significant pulmonary arterial hypertension and right ventricular hypertrophy in comparison with their corresponding drug intervention groups (HD, MD, PD, PMD) and normal control group (N) (P < 0.01). For example, mPAP (mm Hg)(1 mm Hg = 0.133 kPa):N: 18.10 +/- 1.45, H: 27.20 +/- 1.55, HD: 23.90 +/- 2.13; Fulton Inedx(%):N: 23.41 +/- 1.84, H: 34.44 +/- 2.70, HD: 27.55 +/- 2.45. (2) The percent vascular wall thickness (WT%) and percentage of muscularization of non-muscular pulmonary arterioles were significantly increased in all model groups compared with drug intervention groups and normal group (P < 0.01). For example, WT%:N: 10.90 +/- 3.11, H:41.41 +/- 5.21, HD: 17.73 +/- 3.12; Muscularization(%):N: 13.83 +/- 3.72, H: 44.93 +/- 2.43, HD: 29.89 +/- 4.45. (3) The activity of MMPs was inhibited by doxycycline effectively as assessed by gelatin zymography (P < 0.01). For example, the activity of MMP2 (A x 10(3)):N: 1.43 +/- 0.24, H: 3.58 +/- 0.28, HD: 2.29 +/- 0.31.</p><p><b>CONCLUSION</b>Doxycycline attenuated PH and associated pulmonary vascular remodeling in all rat PH models. The study suggests that high expression and enhanced activity of MMPs may play a brutial role in the development of PH. Such phenomenon seems to be common in a variety of PH models of different etiology.</p>

Expression of connective tissue growth factor and its down-regulation by simvastatin administration in pulmonary hypertensive rats / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore the role of expression of connective tissue growth factor (CTGF) in pulmonary vascular remodeling of pulmonary hypertensive rats, and investigate the regulation of CTGF expression by simvastatin in this animal model.</p><p><b>METHODS</b>Eighty male Sprague-Dawley rats (350 to 400 g) were randomized to 7 groups. The rats in group PM(1 - 21) (n = 10) and PM(1 - 35) (n = 12) were treated with pneumonectomy + monocrotaline (MCT), and sacrificed at the 21st or 35th experimental day;those in groups PMS(1 - 35) (n = 12), PMS(21 - 35) (n = 12), PMV(1 - 35) (n = 12) and PMV(21 - 35) (n = 12) were given daily lavage of simvastatin (or vehicle) as intervention measure which began from the 1st and 21st experimental days, respectively; additional 10 rats were used as control without any intervention. The animals were sacrificed at the end of experiment (35 th day) as hemodynamic measurements and study on the morphological parameters relevant to pulmonary vascular remodeling were performed on each group of rats. The expression of ET-1 mRNA, CTGF mRNA and protein, and synthesis of collagen in these pneumonectomized, MCT-treated rats were compared between control and rats treated with simvastatin.</p><p><b>RESULTS</b>Rats in PM(1 - 35) Group developed severe PAH (mPAP = 39.75 +/- 3.62 mm Hg) (1 mm Hg = 0.133 kPa), right ventricular hypertrophy [RV/(LV + S) ratio = 0.627 +/- 0.040], and arterial medial hypertrophy (WT% = 61.73 +/- 5.39), these parameters of the control animals were 17.10 +/- 1.20 mm Hg, 0.262 +/- 0.018 and 14.71 +/- 1.16, respectively. CTGF mRNA and protein were mainly located in pulmonary arterial smooth muscle cells and interstitial macrophage shown by in situ hybridization and immunohistochemistry, respectively. The expression of ET-1 mRNA and CTGF mRNA detected by fluorescent quantitative RT-PCR in Group PM(1 - 35) were significantly increased in comparison with controls, and so did the CTGF protein expression determined by Western blotting in these diseased rats. The content of hydroxyproline (1.30 +/- 0.19 microg/mg wet lung) was remarkably higher than that of control animals (0.56 +/- 0.10 microg/mg wet lung). The up-regulation of ET-1 and CTGF gene expression, and elevated synthesis of hydroxyproline were reversed in rats intervened with simvastatin. The pulmonary hypertension, right ventricular hypertrophy and medial hypertrophy were attenuated in all simvastatin-treated rats no matter the intervention was initiated from the beginning or midway of the study.</p><p><b>CONCLUSION</b>The up-regulation of CTGF gene expression may play an important role in the development of pulmonary vascular remodeling in PAH. Simvastatin can prevent and, to some extent, reverse the vascular remodeling via down-regulation of CTGF gene expression.</p>

Effect of triptolide on the expression of matrix metalloproteinases 2 and 9 in lungs of experimental pulmonary hypertension / 中国当代儿科杂志

<p><b>OBJECTIVE</b>It has been shown that triptolide can attenuate pulmonary arterial hypertension in rats. This study was designed to investigate the therapeutic effect of triptolide on pulmonary hypertension in rats and possible mechanisms.</p><p><b>METHODS</b>Sixty Sprague-Dawley (SD) rats were randomly divided into 6 groups: normal control, model, continuous triptolide-treated, delayed triptolide-treated and two placebo groups for continuous and delayed fashions (n=10 each). The rats from the last 5 groups were injected with monocrotaline (MCT, 60 mg/kg) on day 7 after left pneumonectomy. The rats in the continuous triptolide-treated group received therapy from day 5 to 35 with triptolide (0.25 mg/kg intraperitoneally, every other day) and those in the delayed triptolide-treated received therapy with triptolide (0.20 mg/kg intraperitoneally, daily) from day 21 to 35 after operation. The hemodynamic parameters were detected by catheterization and the pathologic changes of small pulmonary arteries were evaluated by light microscopy 5 weeks post-operation. The expression of matrix metalloproteinases (MMPs) was assessed by immunohistochemistry and quantitative fluorescence PCR of relevant (MMP2 and MMP9) mRNAs.</p><p><b>RESULTS</b>By day 35 after operation, the mean pulmonary arterial pressure (mPAP, 38.10+/-1.20 vs 16.70+/-1.16 mmHg)the ratio of right ventricle/left ventricle plus septum [RV/(LV+S), 62.45+/-5.28% vs 22.76 +/-3.01%] and the vessel obstructive scores (VOS, 1.736 +/-0.080 vs 0.000 +/-0.000) increased significantly in the Model group compared with those of the normal control group (P < 0.01). The expression of MMP2 and MMP9 and their mRNA expression in lung tissues obviously also elevated in the Model group (P < 0.05). The continuous and the delayed triptolide-treated groups had significantly lower mPAP (20.80+/-1.03 and 26.20+/-1.03 mmHg, respectively) and less right ventricular hypertrophy and pulmonary arterial neointimal formation compared with the model and the placebo groups. The two treated groups also demonstrated decreased expression of MMP2 and MMP9 and their mRNA expression in lung tissues. There were significant differences in mPAP, RV/(LV+S) and VOS between the two triptolide-treated groups.</p><p><b>CONCLUSIONS</b>Triptolide attenuates the development of pulmonary hypertention and right ventricular hypertrophy and promotes regression of pulmonary arterial neointimal formation in pneumonectomized rats that received MCT, possibly through an inhibition of MMPs activity.</p>

Interventional approach to the treatment of aneurysms of the perimembranous ventricular septal defects / 中华儿科杂志

<p><b>OBJECTIVES</b>To explore applicable protocol for the positioning of ventricular septal defect (VSD) occluder and the selection of the device by retrospective analysis of transcatheter closure approach to the aneurysms of the perimembranous VSD.</p><p><b>METHODS</b>Thirty-five cases of perimembranous VSD with septal aneurysm (19 males and 16 females) from May, 2004 to May, 2005 were included, with a mean age of 5.3 y and mean weight of 17.6 kg. Their angiographic and ultrasound data, and interventional processes were analyzed. Seven segments of the aneurysms were assessed: the diameter of the defect on the left ventricle, the diameter of the defect on the right ventricle, the thickness of ventricular septum, the distance from the farthest end of the aneurysm to the defect, the diameter of the widest part of the aneurysm and the distance between the two farthest orifices on the aneurysm.</p><p><b>RESULTS</b>Sixteen cystiform aneurysms and nineteen tubiform ones were identified with left ventricular angiography. The diameters of the orifices of aneurysms and the diameters of the VSDs ranged from 1.5 mm to 4.1 mm and 2.7 mm to 11.9 mm, separately, with the mean of 2.9 mm and 4.3 mm. From the echocardiography, the distances of the rim of defect to the aortic valve ranged from 2.0 mm to 7.0 mm, with the mean of 4.3 mm. All the interventions were successfully done with symmetrical devices from 4 mm to 14 mm. The left disc of the device was positioned at the defect surface from the left ventricle in 29 cases, and was released at the left side of the orifice in 3 cases.</p><p><b>CONCLUSIONS</b>The positioning of the left disc is mostly determined by the condition for the correct formation of the right disc in the right ventricle after deploying. Generally the defect surface in the left ventricle is most ideal to release the left disc of the device. If the body of aneurysm was too long for the right disc to restore its configuration, the left disc should be released on the left side of the orifice. The selection of device size is determined by the placement of the left disc. When the left disc is to be released at the defect surface in the left ventricle, the device size should be equal to or 1 to 2 mm larger than the diameter of the defect on the left ventricle. When the left disc is to be deployed on the left side of an orifice, the device size should be equal to or 1 mm larger than the defect diameter on the left ventricle when there is a single orifice. In the case of multiple orifices, the minimal size of the device which can cover all the orifices should be selected.</p>

Differences of Angiotensin II receptor expression between systemic and pulmonary circulation in children with left-to-right shunt congenital cardiac lesions / 中国当代儿科杂志

<p><b>OBJECTIVE</b>It has been shown that angiotensin converting enzyme inhibitors (ACEI) can reduce the ratio of pulmonary and systemic circulation blood flow (Qp/Qs) and thus decrease the blood flow of left-to-right shunt in children with left-to-right shunt congenital cardiac lesions. This suggests that there are differences in the expression of Angiotensin II receptors between systemic and pulmonary circulation. This study aimed to explore the differences of Angiotensin II receptors type 1 and type 2 (AT1 and AT2 receptors) expression between systemic and pulmonary circulation in children with left-to-right shunt congenital cardiac lesions.</p><p><b>METHODS</b>Lung and skeletal muscular tissues were obtained from 20 children with left-to-right shunt congenital cardiac lesions by biopsy during operation. The specimens were stained by immunohistochemistry techniques for AT1 and AT2 receptors. The technique of morphometric analysis was used to measure the immunoreactivity of AT1 and AT2 receptors (expressed by IOD values) of pulmonary, skeletal muscular and pleural small vascular wall the diameter of which was 15-100 microm.</p><p><b>RESULTS</b>The immunoreactivities of AT1 and AT2 receptors of pulmonary small vascular walls [(124 +/- 95)x10(3) and (85 +/- 62)x10(3) respectively] were significantly lower than those of skeletal muscular [(219 +/- 156)x10(3) and (155 +/- 139)x10(3) respectively] and those of pleural small vascular walls [(279 +/- 191)x10(3) and (175 +/- 128)x10(3) respectively] in children with left-to-right shunt congenital cardiac lesions (P < 0.05).</p><p><b>CONCLUSIONS</b>The expression of AT1 and AT2 receptors in small vascular walls of systemic circulation was higher than that of pulmonary circulation in children with left-to-right shunt congenital cardiac lesions.</p>

Clinical value of serum matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 for the prediction and early diagnosis of coronary artery lesion in patients with Kawasaki disease / 中华儿科杂志

<p><b>OBJECTIVE</b>Kawasaki disease (KD) complicated with coronary artery lesion (CAL) seriously threatens survival quality and life of patients, suggesting that it is very important to early predict the risk of CAL and to early diagnose the disease. Nevertheless, up to now there has been no specific clinical biochemical marker for it because of the poor understanding of the pathological process of KD with CAL. Matrix metalloproteinases (MMPs) and their specific tissue inhibitor of metalloproteinases (TIMPs) play an important role in arterial wall extracellular matrix breakdown and remodeling and are involved in CAL in other diseases. In the present study the practical value of serum MMP-9 and TIMP-1 levels in the prediction and early diagnosis of CAL in KD patients was investigated.</p><p><b>METHODS</b>All subjects were from Chinese population. Serum levels of MMP-9 and TIMP-1 were measured by rapid one-step sandwich enzyme immunoassay in 59 KD patients including 15 with CAL and 44 without CAL by 2 D-echocardiography and coronary angiography, and 20 normal healthy children as controls. Blood samples of patients were obtained before and after intravenous immunoglobulin (IVIG) treatment in acute stage, subacute stage and convalescent stage as well. Serum MMP-9 and TIMP-1 levels and the ratio of MMP-9/TIMP-1 were compared by statistical method in KD patients and controls, as well as in KD with CAL and without CAL.</p><p><b>RESULTS</b>In acute stage serum MMP-9 and TIMP-1 levels and the ratio of MMP-9/TIMP-1 were higher (P < 0.01) in patients with KD than those in healthy children. After IVIG treatment in KD patients serum MMP-9 level and the ratio of MMP-9/TIMP-1 decreased (P < 0.01). Before IVIG treatment serum MMP-9 level and the ratio of MMP-9/TIMP-1 were higher (P < 0.01) in patients with CAL than those in patients without CAL, and in acute stage after IVIG treatment serum MMP-9 level of KD patients with CAL was still higher than that of KD patients without CAL.</p><p><b>CONCLUSION</b>In acute stage of KD serum MMP-9 level and the ratio of MMP-9/TIMP-1 were higher in patients with CAL than those in patients without CAL, suggesting that during acute phase of KD the great increase in serum MMP-9 and the imbalance of the MMP-9/TIMP-1 ratio might be high risk factors of KD coronary artery lesion. Therefore, the measurement of serum MMP-9 and TIMP-1 might be of important clinical value in the prediction and the early diagnosis of KD with coronary artery lesion.</p>