Shuming Wu

A reliable rabbit model for hyperkinetic pulmonary hypertension

OBJECTIVE To study the mechanisms of vascular remodeling and increased vascular reactivity, a reliable, economic, easy, and stable animal model of hyperkinetic pulmonary hypertension is needed. The purpose of this study was to construct an animal model of hyperkinetic pulmonary arterial hypertension by chronic systemic-pulmonary shunt in young rabbits. METHODS Thoracotomy was performed through a midsternal incision in 1-month-old rabbits, and anastomosis between the left carotid artery and pulmonary artery trunk created a chronic left-to-right shunt. After 3 months, the shunted artery was checked by echocardiography. Systolic, diastolic, and mean pulmonary arterial pressures were measured by microcatheterization. The pathologic changes of small pulmonary arteries were observed after staining with hematoxylin and eosin. Thickness and area indices were calculated. RESULTS High-flow pulmonary hypertension was successfully established in 24 rabbits 3 months after operation. Relative to a sham operation group, the systolic, diastolic, and mean pulmonary arterial pressures were obviously increased in the experimental group (P < .05). Histologic examination showed that the thickness of arterial wall increased, the lumen became narrowed, and thickness and area indices increased in small pulmonary arteries (P < .05). CONCLUSIONS We constructed a model mimicking the aberrant hemodynamic state in children with congenital heart disease with increased pulmonary blood flow to produce early characteristic morphology of hyperkinetic pulmonary hypertension. This method may provide an economic, easy, and stable animal model to study the mechanisms of pulmonary vascular remodeling in hyperkinetic pulmonary hypertension.

Ethyl pyruvate ameliorates monocrotaline-induced pulmonary arterial hypertension in rats.

Background: Ethyl pyruvate (EP) is an anti-inflammatory and anti-oxidant agent associated with many diseases. In this study, we evaluated whether EP could attenuate monocrotaline-induced pulmonary arterial hypertension (PAH). Methods: A PAH model was established by subcutaneously injecting a single dose of monocrotaline (60 mg/kg). And then a daily intraperitoneal injection of EP (50 mg/kg) was administered on day 1 to day 28 (preventive EP treatment) or day 15 to day 28 (therapeutic EP treatment). Hemodynamic changes were measured by catheterization, and the right ventricle hypertrophy index, the medial wall thickness, and the medial wall areas were also calculated. Enzyme-linked immunosorbent assay and immunohistochemical analysis were used to determine the serum levels and expression of tumor necrosis factor-&agr; (TNF-&agr;), interleukin-6 (IL-6), and endothelin-1 (ET-1) in the lung tissue. Results: Both preventive and therapeutic EP treatment significantly ameliorated hemodynamic changes and vascular remodeling indicators (all P < 0.05). The serum levels and expression of TNF-&agr;, IL-6, and ET-1 in the lung tissue were also significantly decreased (all P < 0.05). Conclusions: EP ameliorates monocrotaline-induced PAH and reverses pulmonary vascular remolding in rats by inhibiting the release of TNF-&agr; and IL-6 and reducing the expression of ET-1.

Establishment and comparison of two reliable hyperkinetic pulmonary hypertension models in rabbits

OBJECTIVES We sought to explore and create a reliable, convenient, and economic hyperkinetic pulmonary artery hypertension (PAH) model and confirm the exact time of establishing a reversible or irreversible model to serve as a platform for future studies. METHODS We used a common carotid artery and jugular vein shunt with an anastomosis and cuff to create a hyperkinetic PAH model in rabbits. At 1, 2, 3, 6, and 12 months postoperatively, the systolic pressure, mean pulmonary arterial pressure, and mean arterial pressure were measured by catheterization and the right ventricle hypertrophy index was calculated. Pathologic changes in the small pulmonary arteries were observed with hematoxylin and eosin staining, and the Heath-Edwards classification system was used to evaluate PAH. RESULTS The anastomosis and cuff graft groups both increased in systolic pressure, mean pulmonary arterial pressure (P<.05), and right ventricle hypertrophy index (P<.05). However, the anastomosis method resulted in a lower mortality rate, greater patency, and overall success rate compared with the cuff graft method (P<.05). Furthermore, from the observed pathologic changes and the Heath-Edwards classification system, a reversible and an irreversible PAH model was established at 3 and 6 months postoperatively, respectively. CONCLUSIONS The common carotid artery and jugular vein anastomosis method is a stable hyperkinetic PAH model in rabbits. Reversible and irreversible PAH models were established at 3 and 6 months postoperatively, respectively.

Pretreatment with intraluminal rapamycin nanoparticle perfusion inhibits neointimal hyperplasia in a rabbit vein graft model

Purpose Poly lactic-co-glycolic acid nanoparticles (PLGA-NP) are widely used as a biodegradable biomaterial in medicine. Rapamycin-eluting stents have been used for prevention of restenosis during surgery. This study investigated the effect of pretreatment with intraluminal perfusion of carbopol-encapsulated rapamycin-loaded PLGA nanoparticles (RAP-PLGA-NP) on neointimal hyperplasia in a rabbit vein graft model. Methods A segment of common carotid artery was replaced with a segment of external jugular vein in 60 rabbits which were then separated into four treatment groups, ie, Group 1, in which vein grafts were pretreated with intraluminal RAP-PLGA-NP perfusion, Group 2 in which vein grafts underwent equivalent empty vehicle (PLGA-NP) perfusion, Group 3, in which vein grafts received no treatment, and Group 4, which served as a sham operation group receiving normal vein contrast. On postoperative day 28, the grafts and normal veins were harvested for histologic examination, flow cytometry analysis, and high-performance liquid chromatography measurement. Results Compared with Group 1, the intima of the grafts were thickened, the ratio of intimal area to vessel area increased, and the collagen volume index of the vein grafts increased significantly in Groups 2 and 3. The cell proliferation index in Group 1 (21.11 ± 3.15%) was much lower than that in Group 2 (30.35 ± 2.69%) and in Group 3 (33.86 ± 8.72%). By high-performance liquid chromatography measurement, retention of rapamycin was detected in Group 1 (11.2 ± 0.37 μg/10 mg) 28 days after single drug perfusion. Conclusion Pretreatment with intraluminal RAP-PLGA-NP perfusion may inhibit neointimal hyperplasia in vein grafts by penetrating into local tissue and limiting cell proliferation.

Oxygenation impairment after total arch replacement with a stented elephant trunk for type-A dissection

Objective: To study the risk factors of oxygenation impairment in patients with type‐A acute aortic dissection who underwent total arch replacement with a stented elephant trunk. Methods: In this study, 169 consecutive patients were enrolled who were diagnosed with type‐A acute aortic dissection and underwent a total arch replacement procedure at the Qilu Hospital of Shandong University between January 2015 and February 2017. Postoperative oxygenation impairment was defined as arterial oxygen partial pressure/inspired oxygen fraction ≤ 200 with positive end expiratory pressure ≥ 5 cm H2O that occurred within 72 hours of surgery. Perioperative clinical characteristics of all patients were collected and univariable analyses were performed. Risk factors associated with oxygenation impairment identified by univariable analyses were included in the multivariable regression analysis. Results: The incidence of postoperative oxygenation impairment was 48.5%. Postoperative oxygenation impairment was associated with prolonged mechanical ventilation time, intensive care unit stay, and hospital stay. Multivariable regression analysis demonstrated that body mass index (odds ratio [OR], 1.204; 95% confidence interval [CI], 1.065–1.361; P = .003), preoperative oxygenation impairment (OR, 9.768; 95% CI, 4.159–22.941; P < .001), preoperative homocysteine (OR, 1.080; 95% CI, 1.006–1.158; P = .032), circulatory arrest time (OR, 1.123; 95% CI, 1.044–1.207; P = .002), and plasma transfusion (OR, 1.002; 95% CI, 1.001–1.003; P = .002) were significantly associated with postoperative oxygenation impairment. Conclusions: Postoperative oxygenation impairment is a common complication of surgery for type‐A acute aortic dissection. Body mass index, preoperative oxygenation impairment, preoperative homocysteine, circulatory arrest time, and plasma transfusion were independent risk factors for oxygenation impairment after a total arch replacement procedure.

Transfection of Human Hepatocyte Growth Factor Gene Inhibits Advancing Pulmonary Arterial Hypertension Induced by Shunt Flow in a Rabbit Model

We investigated gene transfer with human hepatocyte growth factor (HGF) to suppress pulmonary arterial hypertension (PAH) produced by an arteriovenous shunt in a rabbit model. The rabbit model of advanced PAH was used to show that HGF targets pulmonary arteriolar endothelial cells and inhibits disease progression. In the PAH rabbit model transfected with the HGF gene, hemodynamic abnormalities and right ventricular hypertrophy were prevented, as confirmed by invasive measurements and electrocardiographic examinations. In addition to augmented expression of HGF, an increased number of pulmonary arterioles were detected by immunohistochemical analysis. Western Blot and real-time reverse transcriptase-polymerase chain reaction indicated increased protein and mRNA levels of HGF and endothelial nitricoxide synthase (eNOS) in lungs after HGF transfection. Notably, exogenous HGF reduced lung expression of endothelin-1 (ET-1), which was critically involved in PAH-related pathologic changes. Our results suggested that HGF transfection suppresses PAH induced by shunt flow through enhanced expression of HGF with subsequent regulation of the concentrations of eNOS and ET-1 secreted by endothelial cells thereby promoting angiogenesis in injured lung tissue.

Bone Marrow-Derived Mesenchymal Stem Cells-Mediated Protection Against Organ Dysfunction in Disseminated Intravascular Coagulation Is Associated With Peripheral Immune Responses: PROTECTIVE EFFECTOF BMSCS ON DIC

Disseminated intravascular coagulation (DIC) is a fatal thrombohemorrhagic disorder. Bone marrow‐derived mesenchymal stem cells (BMSCs) are multipotent stem cells that have tremendous therapeutic effect. Our aim was to explore whether the immune mechanisms were associated with BMSCs‐afforded protection against DIC. We generated a rat model of DIC by lipopolysaccharide (LPS, 3 mg/kg) injection via the tail vein. In the treatment group, rats were pre‐treated with 1 × l03, 1 × l04, 1 × l05, and 1 × l06 allogeneic BMSCs before LPS injection. Blood sample was withdrawn from the abdominal aorta at 0 (before), 4, and 8 h after LPS injection and used for biochemical analyses. After experiments, the mice were sacrificed and their organs were harvested and observed by H&E and PTAH staining. Continuous infusion of LPS into the rats gradually impaired the hemostatic parameters and damaged organ functions. However, pre‐treatment with BMSCs dose‐dependently improved the hemostatic parameters. Meanwhile, the treatment significantly suppressed the fibrin microthrombi formation and alleviated liver, heart, lung, and renal injuries. Flow cytometry analysis demonstrated that BMSCs pre‐treatment inhibited LPS‐induced upregulation of CD3+CD8+ T cells and CD3+/CD161a+ NKT cells in the peripheral blood. BMSCs pre‐treatment reversed the upregualtion of the B‐cell population and the percentage of CD43+/CD172a+ monocytes in the DIC models. Finally, BMSCs pre‐treatment decreased the levels of tumor necrosis factor‐α (TNF‐α), interferon‐γ (IFN‐γ), interleukin‐1β (IL‐1β), and interleukin‐6 (IL‐6) and increased the levels of interleukin‐10 (IL‐10) in LPS‐induced DIC models. Pre‐treatment with BMSCs can reduce coagulation and alleviate organ dysfunction via peripheral immune responses in LPS‐induced DIC rat model. J. Cell. Biochem. 118: 3184–3192, 2017.

BMSCs pre-treatment ameliorates inflammation-related tissue destruction in LPS-induced rat DIC model

This study aimed to investigate the effect of bone marrow-derived mesenchymal stem cells (BMSCs) on disseminated intravascular coagulation (DIC) model rats and to further explore the underlying mechanism. A rat model of lipopolysaccharide (LPS)-induced DIC was successfully established, as indicated by impaired plasma hemostatic parameters and damaged organ functions in rats. Importantly, pre-treatment with rat allogeneic BMSCs before LPS injection significantly alleviated systemic intravascular coagulation, reduced plasma levels of organ dysfunction indicators and pro-inflammatory cytokines, suppressed fibrin microthrombi formation, ameliorated liver, heart, and renal injuries, and increased 24-hour survival rates in LPS-induced DIC rats. The protection of BMSCs against DIC was in a moderately dose-dependent manner. Further investigation revealed that BMSCs co-cultured with peripheral blood mononuclear cells (PBMCs) significantly inhibited the LPS-stimulated PBMCs proliferation and the release of pro-inflammatory cytokines from PBMCs. Of note, upregulation of immunosuppressive factors including indoleamine 2,3-dioxygenase and interleukin-10, which was induced by interferon-γ, contributed to BMSCs-mediated inhibition of LPS-stimulated PBMCs proliferation. These effects do not depend on the direct cell–cell contact. In conclusion, BMSCs pre-treatment ameliorates inflammation-related tissue destruction in LPS-induced DIC model rats. The protection of BMSCs may be attributed to their anti-inflammatory and immunomodulatory properties, which render BMSCs a promising source for stem cell-based therapeutic approaches in inflammation-related DIC.