Estrogen exposure, obesity and thyroid disease in women with severe pulmonary hypertension

Severe pulmonary hypertension is a lethal group of disorders which preferentially afflicts women. It appears that in recent years the patient profile has shifted towards older, obese, and postmenopausal women, suggesting that endocrine factors may be important. Several studies have revealed an increased prevalence of thyroid disease in these patients, but no studies have evaluated for a coexistence of endocrine factors. In particular, no studies have attempted to evaluate for concurrent thyroid disease, obesity and long-term estrogen exposure in patients. 88 patients attending the Pulmonary Hypertension Association 8th International meeting completed a questionnaire and were interviewed. Information was collected regarding reproductive history, height, weight, and previous diagnosis of thyroid disease. 46% met criteria for obesity. 41% reported a diagnosis of thyroid disease. 81% of women reported prior use of hormone therapy. 70% reported greater than 10 years of exogenous hormone use. 74% of female patients reported two or more of potentially disease modifying endocrine factors (obesity, thyroid disease or estrogen therapy). The coexistent high prevalence in our cohort of exogenous estrogen exposure, thyroid disease and obesity suggests that an interaction of multiple endocrine factors might contribute to the pathogenesis of pulmonary hypertension and may represent epigenetic modifiers in genetically-susceptible individuals

ID3 Contributes to the Acquisition of Molecular Stem Cell-Like Signature in Microvascular Endothelial Cells: Its implication for understanding microvascular diseases

While significant progress has been made to advance our knowledge of microvascular lesion formation, yet the investigation of how stem-like cells may contribute to the pathogenesis of microvascular diseases is still in its infancy. We assessed whether the inhibitor of DNA binding and differentiation 3 (ID3) contributes to the acquisition of a molecular stem cell-like signature in microvascular endothelial cells. The effects of stable ID3 overexpression and SU5416 treatment — a chemical inducer of microvascular lesions, had on the stemness signature was determined by flow cytometry, immunoblot, and immunohistochemistry. Continuous ID3 expression produced a molecular stemness signature consisting of CD133+ VEGFR3+ CD34+ cells. Cells exposed to SU5416 showed positive protein expression of ID3, VEGFR3, CD34 and increased expression of pluripotent transcription factors Oct-4 and Sox-2. ID3 overexpressing cells supported the formation of a 3-D microvascular lesion co-cultured with smooth muscle cells. In addition, in vivo microvascular lesions from SuHx rodent model showed an increased expression of ID3, VEGFR3, and Pyk2 similar to SU5416 treated human endothelial cells. Further investigations into how normal and stem-like cells utilize ID3 may open up new avenues for a better understanding of the molecular mechanisms which are underlying the pathological development of microvascular diseases

Determinants of an elevated pulmonary arterial pressure in patients with pulmonary arterial hypertension

Given the difficulty of diagnosing early-stage pulmonary arterial hypertension (PAH) due to the lack of signs and symptoms, and the risk of an open lung biopsy, the precise pathological features of presymptomatic stage lung tissue remain unknown. It has been suggested that the maximum elevation of the mean pulmonary arterial pressure (Ppa) is achieved during the early symptomatic stage, indicating that the elevation of the mean Ppa is primarily driven by the pulmonary vascular tone and/or some degree of pulmonary vascular remodeling completed during this stage. Recently, the examination of a rat model of severe PAH suggested that the severe PAH may be primarily determined by the presence of intimal lesions and/or the vascular tone in the early stage. Human data seem to indicate that intimal lesions are essential for the severely increased pulmonary arterial blood pressure in the late stage of the disease. However, many questions remain. For instance, how does the pulmonary hemodynamics change during the course of the disease, and what drives the development of severe PAH? Although it is generally acknowledged that both pulmonary vascular remodeling and the vascular tone are important determinants of an elevated pulmonary arterial pressure, which is the root cause of the time-dependent progression of the disease? Here we review the recent histopathological concepts of PAH with respect to the progression of the lung vascular disease

Sirt1 expression is associated with CD31 expression in blood cells from patients with chronic obstructive pulmonary disease

Background: Cigarette smoke induced oxidative stress has been shown to reduce silent information regulator 1 (Sirt1) levels in lung tissue from smokers and patients with COPD patients. Sirt1 is known to inhibit endothelial senescence and may play a protective role in vascular cells. Endothelial progenitor cells (EPCs) are mobilized into circulation under various pathophysiological conditions, and are thought to play an important role in tissue repair in chronic obstructive lung disease (COPD). Therefore, Sirt1 and EPC-associated mRNAs were measured in blood samples from patients with COPD and from cultured CD34+ progenitor cells to examine whether these genes are associated with COPD development. Methods: This study included 358 patients with a smoking history of more than 10 pack-years. RNA was extracted from blood samples and from CD34+ progenitor cells treated with cigarette smoke extract (CSE), followed by assessment of CD31, CD34, Sirt1 mRNA, miR-34a, and miR-126-3p expression by real-time RT-PCR. Results: The expression of CD31, CD34, Sirt1 mRNAs, and miR-126-3p decreased and that of miR-34a increased in moderate COPD compared with that in control smokers. However, no significant differences in these genes were observed in blood cells from patients with severe COPD compared with those in control smokers. CSE significantly decreased Sirt1 and increased miR-34a expression in cultured progenitor cells. Conclusion: Sirt1 expression in blood cells from patients with COPD could be a biomarker for disease stability in patients with moderate COPD. MiR-34a may participate in apoptosis and/or senescence of EPCs in smokers. Decreased expression of CD31, CD34, and miR-126-3p potentially represents decreased numbers of EPCs in blood cell from patients with COPD

Fenretinide Causes Emphysema, Which Is Prevented by Sphingosine 1-Phoshate

Sphingolipids play a role in the development of emphysema and ceramide levels are increased in experimental models of emphysema; however, the mechanisms of ceramide-related pulmonary emphysema are not fully understood. Here we examine mechanisms of ceramide-induced pulmonary emphysema. Male Sprague-Dawley rats were treated with fenretinide (20 mg/kg BW), a synthetic derivative of retinoic acid that causes the formation of ceramide, and we postulated that the effects of fenretinide could be offset by administering sphingosine 1-phosphate (S1P) (100 µg/kg BW). Lung tissues were analyzed and mean alveolar airspace area, total length of the alveolar perimeter and the number of caspase-3 positive cells were measured. Hypoxia-inducible factor alpha (HIF-1α), vascular endothelial growth factor (VEGF) and other related proteins were analyzed by Western blot analysis. Immunohistochemical analysis of HIF-1α was also performed. Ceramide, dihydroceramide, S1P, and dihydro-S1P were measured by mass spectrometer. Chronic intraperitoneal injection of fenretinide increased the alveolar airspace surface area and increased the number of caspase-3 positive cells in rat lungs. Fenretinide also suppressed HIF-1α and VEGF protein expression in rat lungs. Concomitant injection of S1P prevented the decrease in the expression of HIF-1α, VEGF, histone deacetylase 2 (HDAC2), and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) protein expression in the lungs. S1P injection also increased phosphorylated sphingosine kinase 1. Dihydroceramide was significantly increased by fenretinide injection and S1P treatment prevented the increase in dihydroceramide levels in rat lungs. These data support the concept that increased de novo ceramide production causes alveolar septal cell apoptosis and causes emphysema via suppressing HIF-1α. Concomitant treatment with S1P normalizes the ceramide-S1P balance in the rat lungs and increases HIF-1α protein expression via activation of sphingosine kinase 1; as a consequence, S1P salvages fenretinide induced emphysema in rat lungs

Genomic approaches to research in pulmonary hypertension

Genomics, or the study of genes and their function, is a burgeoning field with many new technologies. In the present review, we explore the application of genomic approaches to the study of pulmonary hypertension (PH). Candidate genes, important to the pathobiology of the disease, have been investigated. Rodent models enable the manipulation of selected genes, either by transgenesis or targeted disruption. Mutational analysis of genes in the transforming growth factor-β family have proven pivotal in both familial and sporadic forms of primary PH. Finally, microarray gene expression analysis is a robust molecular tool to aid in delineating the pathobiology of this disease

CXCR4 Inhibition Ameliorates Severe Obliterative Pulmonary Hypertension and Accumulation of C-Kit+ Cells in Rats

Successful curative treatment of severe pulmonary arterial hypertension with luminal obliteration will require a thorough understanding of the mechanism underlying the development and progression of pulmonary vascular lesions. But the cells that obliterate the pulmonary arterial lumen in severe pulmonary arterial hypertension are incompletely characterized. The goal of our study was to evaluate whether inhibition of CXC chemokine receptor 4 will prevent the accumulation of c-kit+ cells and severe pulmonary arterial hypertension. We detected c-kit+­ cells expressing endothelial (von Willebrand Factor) or smooth muscle cell/myofibroblast (α-smooth muscle actin) markers in pulmonary arterial lesions of SU5416/chronic hypoxia rats. We found increased expression of CXC chemokine ligand 12 in the lung tissue of SU5416/chronic hypoxia rats. In our prevention study, AMD3100, an inhibitor of the CXC chemokine ligand 12 receptor, CXC chemokine receptor 4, only moderately decreased pulmonary arterial obliteration and pulmonary hypertension in SU5416/chronic hypoxia animals. AMD3100 treatment reduced the number of proliferating c-kit+ α-smooth muscle actin+ cells and pulmonary arterial muscularization and did not affect c-kit+ von Willebrand Factor+ cell numbers. Both c-kit+ cell types expressed CXC chemokine receptor 4. In conclusion, our data demonstrate that in the SU5416/chronic hypoxia model of severe pulmonary hypertension, the CXC chemokine receptor 4-expressing c-kit+ α-smooth muscle actin+ cells contribute to pulmonary arterial muscularization. In contrast, vascular lumen obliteration by c-kit+ von Willebrand Factor+ cells is largely independent of CXC chemokine receptor 4

Vascular endothelial growth factor receptor 3 signaling contributes to angioobliterative pulmonary hypertension

The mechanisms involved in the development of severe angioobliterative pulmonary arterial hypertension (PAH) are multicellular and complex. Many of the features of human severe PAH, including angioobliteration, lung perivascular inflammation, and right heart failure, are reproduced in the Sugen 5416/chronic hypoxia (SuHx) rat model. Here we address, at first glance, the confusing and paradoxical aspect of the model, namely, that treatment of rats with the antiangiogenic vascular endothelial growth factor (VEGF) receptor 1 and 2 kinase inhibitor, Sugen 5416, when combined with chronic hypoxia, causes angioproliferative pulmonary vascular disease. We postulated that signaling through the unblocked VEGF receptor VEGFR3 (or flt4) could account for some of the pulmonary arteriolar lumen-occluding cell growth. We also considered that Sugen 5416-induced VEGFR1 and VEGFR2 blockade could alter the expression pattern of VEGF isoform proteins. Indeed, in the lungs of SuHx rats we found increased expression of the ligand proteins VEGF-C and VEGF-D as well as enhanced expression of the VEGFR3 protein. In contrast, in the failing right ventricle of SuHx rats there was a profound decrease in the expression of VEGF-B and VEGF-D in addition to the previously described reduction in VEGF-A expression. MAZ51, an inhibitor of VEGFR3 phosphorylation and VEGFR3 signaling, largely prevented the development of angioobliteration in the SuHx model; however, obliterated vessels did not reopen when animals with established PAH were treated with the VEGFR3 inhibitor. Part of the mechanism of vasoobliteration in the SuHx model occurs via VEGFR3. VEGFR1/VEGFR2 inhibition can be initially antiangiogenic by inducing lung vessel endothelial cell apoptosis; however, it can be subsequently angiogenic via VEGF-C and VEGF-D signaling through VEGFR3

Enhanced Interleukin-1 Activity Contributes to Exercise Intolerance in Patients with Systolic Heart Failure

Contains fulltext : 107753.pdf (publisher's version ) (Open Access)BACKGROUND: Heart failure (HF) is a complex clinical syndrome characterized by impaired cardiac function and poor exercise tolerance. Enhanced inflammation is associated with worsening outcomes in HF patients and may play a direct role in disease progression. Interleukin-1beta (IL-1beta) is a pro-inflammatory cytokine that becomes chronically elevated in HF and exerts putative negative inotropic effects. METHODS AND RESULTS: We developed a model of IL-1beta-induced left ventricular (LV) dysfunction in healthy mice that exhibited a 32% reduction in LV fractional shortening (P<0.001) and a 76% reduction in isoproterenol response (P<0.01) at 4 hours following a single dose of IL-1beta 3 mcg/kg. This phenotype was reproducible in mice injected with plasma from HF patients and fully preventable by pretreatment with IL-1 receptor antagonist (anakinra). This led to the design and conduct of a pilot clinical to test the effect of anakinra on cardiopulmonary exercise performance in patients with HF and evidence of elevated inflammatory signaling (n = 7). The median peak oxygen consumption (VO(2)) improved from 12.3 [10.0, 15.2] to 15.1 [13.7, 19.3] mL . kg(-1) . min(-1) (P = 0.016 vs. baseline) and median ventilator efficiency (V(E)/VCO(2) slope) improved from 28.1 [22.8, 31.7] to 24.9 [22.9, 28.3] (P = 0.031 vs. baseline). CONCLUSIONS: These findings suggest that IL-1beta activity contributes to poor exercise tolerance in patients with systolic HF and identifies IL-1beta blockade as a novel strategy for pharmacologic intervention. TRIAL REGISTRATION: ClinicalTrials.gov NCT01300650