姜黄素对高氧致新生鼠支气管肺发育不良的保护作用

目的 研究姜黄素对高氧暴露致新生鼠支气管肺发育不良的影响,探讨其作用机制.方法 给予出生6 h内的SD大鼠持续60%氧暴露14d建立肺损伤模型.通氧的同时予姜黄索100 ms/(kg·d)灌胃.观察肺组织病理学改变,进行辐射状肺泡计数(RAC),末端脱氧核苷酸转移酶介导的dUTP缺口标记技术(TUNEL)检测肺组织细胞凋亡.免疫组化和Western blot法检测肺组织活化半胱氨酸蛋白酶-3(Caspase-3)的表达.结果 与空气对照组相比,随着氧暴露时间的延长,高氧组的大鼠出现肺发育停滞的典型病理表现:肺泡增大、结构简化,肺泡隔增厚.RAC明显减少,肺组织细胞凋亡明显增加,免疫组化和Western blot法均显示肺组织活化Caspase-3表达明显升高.姜黄素能改善损伤的肺病理结构,并在干预14d后使RAC显著增多,肺组织凋亡细胞显著减少,干预4d后肺组织活化Caspase-3显著降低.结论 姜黄素可减轻高氧暴露所致的BPD,可能是通过抗凋亡机制实现其保护作用.     

CTGF disrupts alveolarization and induces pulmonary hypertension in neonatal mice: implication in the pathogenesis of severe bronchopulmonary dysplasia

The pathological hallmarks of bronchopulmonary dysplasia (BPD), one of the most common long-term pulmonary complications associated with preterm birth, include arrested alveolarization, abnormal vascular growth, and variable interstitial fibrosis. Severe BPD is often complicated by pulmonary hypertension characterized by excessive pulmonary vascular remodeling and right ventricular hypertrophy that significantly contributes to the mortality and morbidity of these infants. Connective tissue growth factor (CTGF) is a multifunctional protein that coordinates complex biological processes during tissue development and remodeling. We have previously shown that conditional overexpression of CTGF in airway epithelium under the control of the Clara cell secretory protein promoter results in BPD-like architecture in neonatal mice. In this study, we have generated a doxycycline-inducible double transgenic mouse model with overexpression of CTGF in alveolar type II epithelial (AT II) cells under the control of the surfactant protein C promoter. Overexpression of CTGF in neonatal mice caused dramatic macrophage and neutrophil infiltration in alveolar air spaces and perivascular regions. Overexpression of CTGF also significantly decreased alveolarization and vascular development. Furthermore, overexpression of CTGF induced pulmonary vascular remodeling and pulmonary hypertension. Most importantly, we have also demonstrated that these pathological changes are associated with activation of integrin-linked kinase (ILK)/glucose synthesis kinase-3β (GSK-3β)/β-catenin signaling. These data indicate that overexpression of CTGF in AT II cells results in lung pathology similar to those observed in infants with severe BPD and that ILK/GSK-3β/β-catenin signaling may play an important role in the pathogenesis of severe BPD.     

Epidemiology of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is among the most common and serious sequelae of preterm birth. BPD affects at least one‐quarter of infants born with birth weights less than 1500 g. The incidence of BPD increases with decreasing gestational age and birth weight. Additional important risk factors include intrauterine growth restriction, sepsis, and prolonged exposure to mechanical ventilation and supplemental oxygen. The diagnosis of BPD predicts multiple adverse outcomes including chronic respiratory impairment and neurodevelopmental delay. This review summarizes the diagnostic criteria, incidence, risk factors, and long‐term outcomes of BPD. Birth Defects Research (Part A) 100:145–157, 2014. © 2014 Wiley Periodicals, Inc.     

Mechanisms of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease affecting premature infants with long term effect on lung function into adulthood. Multiple factors are involved in the development of BPD. This review will summarize the different mechanisms leading to this disease and highlight recent bench and clinical research targeted at understanding the role of the mesenchyme (both its cellular and extracellular components) in the pathogenesis of BPD.     

Pulmonary hypertension in bronchopulmonary dysplasia

Pulmonary hypertension is common in bronchopulmonary dysplasia and is associated with increased mortality and morbidity. This pulmonary hypertension is due to abnormal microvascular development and pulmonary vascular remodeling resulting in reduced cross‐sectional area of pulmonary vasculature. The epidemiology, etiology, clinical features, diagnosis, suggested management, and outcomes of pulmonary hypertension in the setting of bronchopulmonary dysplasia are reviewed. In summary, pulmonary hypertension is noted in a fifth of extremely low birth weight infants, primarily those with moderate or severe bronchopulmonary dysplasia, and persists to discharge in many infants. Diagnosis is generally by echocardiography, and some infants require cardiac catheterization to identify associated anatomic cardiac lesions or systemic‐pulmonary collaterals, pulmonary venous obstruction or myocardial dysfunction. Serial echocardiography and B‐type natriuretic peptide measurement may be useful for following the course of pulmonary hypertension. Currently, there is not much evidence to indicate optimal management approaches, but many clinicians maintain oxygen saturation in the range of 91 to 95%, avoiding hypoxia and hyperoxia, and often provide inhaled nitric oxide, sometimes combined with sildenafil, prostacyclin, or its analogs, and occasionally endothelin‐receptor antagonists. Birth Defects Research (Part A) 100:240–246, 2014. © 2014 Wiley Periodicals, Inc.     

Characteristics of bone marrow-derived endothelial progenitor cells in aged mice

Evidence for dysfunction of endothelial repair in aged mice was sought by studying the pattern of induced differentiation, quantity, and function of bone marrow-derived endothelial progenitor cells (EPCs) in aged mice. The CD117-positive stem cell population was separated from bone marrow by magnetic activated cell-sorting system (MACS), and EPCs were defined by demonstrating the expression of CD117+CD34+Flk-1+ by flow cytometry. After 7 days of culture, the number of clones formed was counted, and proliferation and migration of EPCs were analyzed by MTT[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and modified Boyden chamber assay. The results demonstrated that compared to the control group, the quantity of bone marrow-derived CD117+ stem cells and EPCs, as well as the proliferation, migration, the number of clones formed, and phagocytotic function of EPCs were significantly reduced in aged mice. There were no significant differences in the morphology and induced differentiation pattern of EPCs between the aged mouse group and the control group. Authors suggest that the dysfunction of EPCs may serve as a surrogate parameter of vascular function in old mice.     

Altered lung development in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is the main respiratory sequela of extreme prematurity. Its pathophysiology is complex, involving interactions between host and environment, likely to be significantly influenced by genetic factors. Thus, the clinical presentation and histological lesions have evolved over time, along with the reduction in neonatal injuries, and the care of more immature children. Impaired alveolar growth, however, is a lesion consistently observed in BPD, such that it is a key feature in BPD, and is even the dominant characteristic of the so‐called “new” forms of BPD. This review describes the key molecular pathways that are believed to be involved in the genesis of BPD. Much of our understanding is based on animal models, but this is increasingly being enriched by genetic approaches, and long‐term respiratory functional studies. Birth Defects Research (Part A) 100:158–167, 2014. © 2014 Wiley Periodicals, Inc.     

Early endotoxin tolerance is associated with alterations in bone marrow-derived macrophage precursor pools

Early endotoxin tolerance has been defined as the transient period after an initial sublethal exposure to LPS during which a normally responsive individual is rendered hyporesponsive. Little is known about the cellular mechanisms that underlie this phenomenon. In this study, an early tolerance system was established by the injection of mice with 25 micrograms of E. coli K235 LPS. Maximal hyporesponsiveness in response to a challenge injection was observed 3 to 4 days after the initial injection, and normal responsiveness returned by 8 days after the initial exposure to LPS. Further experiments described herein demonstrate that the acquisition and maintenance of the tolerant state coincides temporally with an increase in the number of macrophage progenitor cells in the bone marrow. Cell-sizing profiles of the bone marrow cells from tolerized mice indicate an enrichment for a population of cells that are significantly larger than in bone marrow preparations from control mice. By density gradient sedimentation, it was shown that the denser population of cells from tolerized mice contained the increased numbers of progenitor cells, which, by cytology, were immature monocytic cell types. The increased numbers of macrophage progenitors was sustained after a second (challenge) injection of LPS. These results indicate that early endotoxin tolerance is associated with an increase in a population of bone marrow cells that is enriched for macrophage progenitors and suggests the possibility that the lack of responsiveness observed during the hyporesponsive period is related to a failure of these immature cell types to respond to LPS.     

Postnatal inflammation in the pathogenesis of bronchopulmonary dysplasia

Exposure to hyperoxia, invasive mechanical ventilation, and systemic/local sepsis are important antecedents of postnatal inflammation in the pathogenesis of bronchopulmonary dysplasia (BPD). This review will summarize information obtained from animal (baboon, lamb/sheep, rat and mouse) models that pertain to the specific inflammatory agents and signaling molecules that predispose a premature infant to BPD. Birth Defects Research (Part A) 100:189–201, 2014. © 2014 Wiley Periodicals, Inc.     

Functional defects of culture-grown bone marrow-derived macrophages from autoimmune MRL/MpJ-lpr/lpr mice

To investigate the primary defects and development of macrophages in MRL/MpJ-/pr/lpr (MRL/l) mice, we used a pure population of macrophages derived from bone marrow precursor cells cultured in the presence of L-cell conditioned medium (LCM) as a source of colony stimulating factor. Bone marrow-derived macrophages (BMM phi) from MRL/l mice had lower antigen presenting activity as detected by the induction of antigen-specific T cell proliferation, than age- and sex-matched control mice (CBA/J). Cell surface antigens (Ia and Mac-1) were determined quantitatively by a cell sorter as markers of macrophage differentiation. The BMM phi from MRL/l contained a much smaller number of Ia antigen-positive macrophages than those from normal mice. Treatment of BMM phi with an Ia-inducing of factor (IFN-gamma) markedly increased the expression of Ia antigens. This increase was significantly greater in BMM phi from MRL/l mice than in BMM phi from control mice. Expression of Mac-1 antigen was not different in BMM phi from the two strains. The Fc-mediated phagocytosis of IgG-coated sheep red blood cells was decreased in BMM phi from MRL/l mice compared with those from control mice. The function of nonspecific phagocytosis as measured by latex-bead incorporation was also impaired in MRL/l mice. The functional defects of MRL/l BMM phi found in these experiments are not secondary defects acquired under the influence of environmental signals during development, but are derived from the primary abnormalities which already exist in myeloid stem cells.     

Hematopoietic precursor cells in radiation chimeras restored by bone marrow from thymectomized mice]

Radioprotective capacity of bone marrow CFUs of adult thymectomized mice was studied. Lethally irradiated mice were inoculated with bone marrow of mice thymectomized 8-11 months before. The colony forming capacity and proliferative rate of CFUs were studied 1-7.5 months after obtaining the radiation chimeras. It has been shown that proliferative capacity of bone marrow of adult thymectomized mice was reduced in comparison with that of normal animals. It is related to the decrease (4-fold) of the proliferative rate of bone marrow of thymectomized mice which was inoculated into lethally irradiated recipients 1 month before. We also found that the content of CFUs in bone of those chimeras was reduced later--after 7.5 months. In this period (1-7.5 months) the cellularity of bone marrow did not change.     

Bone marrow-derived HL mitigates bone marrow-derived CETP-mediated decreases in HDL in mice globally deficient in HL and the LDLr

The objective of this study was to determine the combined effects of HL and cholesteryl ester transfer protein (CETP), derived exclusively from bone marrow (BM), on plasma lipids and atherosclerosis in high-fat-fed, atherosclerosis-prone mice. We transferred BM expressing these proteins into male and female double-knockout HL-deficient, LDL receptor-deficient mice (HL^−/−LDLr^−/−). Four BM chimeras were generated, where BM-derived cells expressed 1) HL but not CETP, 2) CETP and HL, 3) CETP but not HL, or 4) neither CETP nor HL. After high-fat feeding, plasma HDL-cholesterol (HDL-C) was decreased in mice with BM expressing CETP but not HL (17 ± 4 and 19 ± 3 mg/dl, female and male mice, respectively) compared with mice with BM expressing neither CETP nor HL (87 ± 3 and 95 ± 4 mg/dl, female and male mice, respectively, P < 0.001 for both sexes). In female mice, the presence of BM-derived HL mitigated this CETP-mediated decrease in HDL-C. BM-derived CETP decreased the cholesterol component of HDL particles and increased plasma cholesterol. BM-derived HL mitigated these effects of CETP. Atherosclerosis was not significantly different between BM chimeras. These results suggest that BM-derived HL mitigates the HDL-lowering, HDL-modulating, and cholesterol-raising effects of BM-derived CETP and warrant further studies to characterize the functional properties of these protein interactions.     

Effects of bone marrow-derived cells on monocrotaline- and hypoxia-induced pulmonary hypertension in mice

Background

Bone marrow -derived cells (BMDCs) can either limit or contribute to the process of pulmonary vascular remodeling. Whether the difference in their effects depends on the mechanism of pulmonary hypertension (PH) remains unknown.

Objectives

We investigated the effect of BMDCs on PH induced in mice by either monocrotaline or exposure to chronic hypoxia.

Methods

Intravenous administration of the active monocrotaline metabolite (monocrotaline pyrrole, MCTp) to C57BL/6 mice induced PH within 15 days, due to remodeling of small distal vessels. Three days after the MCTp injection, the mice were injected with BMDCs harvested from femurs and tibias of donor mice treated with 5-fluorouracil (3.5 mg IP/animal) to deplete mature cells and to allow proliferation of progenitor cells.

Results

BMDCs significantly attenuated PH as assessed by reductions in right ventricular systolic pressure (20 ± 1 mmHg vs. 27 ± 1 mmHg, P ≤ 0.01), right ventricle weight/left ventricle+septum weight ratio (0.29 ± 0.02 vs. 0.36 ± 0.01, P ≤ 0.03), and percentage of muscularized vessels (26.4% vs. 33.5%, P ≤ 0.05), compared to control animals treated with irradiated BMDCs. Tracking cells from constitutive GFP-expressing male donor mice with anti-GFP antibodies or chromosome Y level measurement by quantitative real-time PCR showed BMDCs in the lung. In contrast, chronically hypoxic mice subjected to the same procedure failed to show improvement in PH.

Conclusion

These results show that BMDCs limit pulmonary vascular remodeling induced by vascular injury but not by hypoxia.     

Pentosan polysulfate promotes proliferation and chondrogenic differentiation of adult human bone marrow-derived mesenchymal precursor cells

Introduction  

This study was undertaken to determine whether the anti-osteoarthritis drug pentosan polysulfate (PPS) influenced mesenchymal precursor cell (MPC) proliferation and differentiation.     

Effects of allogeneic bone marrow-derived mesenchymal stem cells on T and B lymphocytes from BXSB mice

Bone marrow-derived mesenchymal stem cells (bMSCs) can differentiate into a number of different cell/tissue types, and also possess immunoregulatory functions. The present study was undertaken to elucidate the exact immunoregulatory effects of allogeneic bMSCs on T- and B-lymphocyte proliferation, activation, and function maturation of BXSB mice, which has been considered as a experimental model for human systemic lupus erythematosus (SLE). We determined that bMSCs from BALB/c mice had inhibitory effects on BXSB mice T-lymphocyte proliferation, but no inhibitory effect on their activation. In addition, they had a significant inhibitory and stimulatory effect on IL-4- and IFN-gamma-producing T cells, respectively. Also, bMSCs had inhibitory effects on the proliferation, activation, and IgG secretion of B lymphocytes. In addition, BALB/c bMSCs had an enhancing effect on CD40 expression and inhibitory effects on CD40 ligand (CD40L) ectopic hyperexpression on B cells from BXSB mice.     

Nutrition of preterm infants in relation to bronchopulmonary dysplasia

Background

The pathogenesis of bronchopulmonary dysplasia (BPD) is multifactorial. In addition to prenatal inflammation, postnatal malnutrition also affects lung development.

Methods

A retrospective study was performed to analyse during the first two weeks of life the total, enteral and parenteral nutrition of premature infants (<31 weeks, birth weight ≤1500 g) born between 08/04 and 12/06.

Results

Ninety-five premature infants were analysed: 26 with BPD (27 ± 1 weeks) and 69 without BPD (28 ± 1 weeks). There was no statistical significant difference in the total intake of fluids, calories, glucose or protein and weight gain per day in both groups. The risk of developing BPD was slightly increased in infants with cumulative caloric intake below the minimal requirement of 1230 kcal/kg and a cumulative protein intake below 43.5 g/kg. Furthermore, the risk of developing BPD was significantly higher when infants had a cumulative fluid intake above the recommended 1840 ml/kg. In infants who developed BPD, the enteral nutrition was significantly lower than in non-BPD infants [456 ml/kg (IQR 744, 235) vs. 685 (IQR 987, 511)]. Infants who did not develop BPD reached 50% of total enteral feeding significantly faster [9.6 days vs. 11.5].

Conclusions

Preterm infants developing BPD received less enteral feeding, even though it was well compensated by the parenteral nutrient supply. Data suggest that a critical minimal amount of enteral feeding is required to prevent development of BPD; however, a large prospective clinical study is needed to prove this assumption.