Search tips
Search criteria

Results 1-11 (11)

Clipboard (0)

Select a Filter Below

Year of Publication
1.  Pulmonary arterial hypertension in a patient with Cowden syndrome and the PTEN mutation 
Pulmonary Circulation  2014;4(4):728-731.
The pathogenesis of pulmonary arterial hypertension (PAH) exhibits many neoplastic-like features. Cowden syndrome is a difficult-to-recognize heritable cancer syndrome caused by a germline mutation in the phosphatase-and-tensin homolog deleted on the chromosome 10 (PTEN) gene. PTEN regulation has been implicated in cancer development and, more recently, PAH pathogenesis. Here we report a case of PAH in a patient with Cowden syndrome and the response to pulmonary vasodilators.
PMCID: PMC4278632  PMID: 25610608
pulmonary hypertension; PTEN mutation; Cowden syndrome
2.  Imatinib in pulmonary arterial hypertension: c-Kit inhibition 
Pulmonary Circulation  2014;4(3):452-455.
Pulmonary arterial hypertension (PAH) is a progressive disease characterized by severe remodeling of the pulmonary artery resulting in increased pulmonary artery pressure and right ventricular hypertrophy and, ultimately, failure. Bone marrow–derived progenitor cells play a critical role in vascular homeostasis and have been shown to be involved in the pathogenesis of PAH. A proliferation of c-Kit+ hematopoietic progenitors and mast cells has been noted in the remodeled vessels in PAH. Imatinib, a tyrosine kinase inhibitor that targets c-Kit, has been shown to be beneficial for patients with PAH. Here we hypothesize that the clinical benefit of imatinib in PAH could be related to c-Kit inhibition of progenitor cell mobilization and maturation into mast cells. As a corollary to the phase 3 study using imatinib in PAH, blood samples were collected from 12 patients prior to starting study drug (baseline) and while on treatment at weeks 4 and 24. Eight were randomized to imatinib and 4 to placebo. Circulating c-Kit+ and CD34+CD133+ hematopoietic progenitors as well as biomarkers of mast cell numbers and activation were measured. Circulating CD34+CD133+ and c-Kit+ progenitor cells as well as c-Kit+/CD34+CD133+ decreased with imatinib therapy (all P < 0.05). In addition, total tryptase, a marker of mast cell load, dropped with imatinib therapy (P = 0.02) and was related to pulmonary vascular resistance (R = 0.7, P = 0.02). The findings support c-Kit inhibition as a potential mechanism of action of imatinib in PAH and suggest that tryptase is a potential biomarker of response to therapy.
PMCID: PMC4278604  PMID: 25621158
pulmonary hypertension; imatinib; c-Kit; progenitor cells; mast cells
3.  Coenzyme Q supplementation in pulmonary arterial hypertension 
Redox Biology  2014;2:884-891.
Mitochondrial dysfunction is a fundamental abnormality in the vascular endothelium and smooth muscle of patients with pulmonary arterial hypertension (PAH). Because coenzyme Q (CoQ) is essential for mitochondrial function and efficient oxygen utilization as the electron carrier in the inner mitochondrial membrane, we hypothesized that CoQ would improve mitochondrial function and benefit PAH patients. To test this, oxidized and reduced levels of CoQ, cardiac function by echocardiogram, mitochondrial functions of heme synthesis and cellular metabolism were evaluated in PAH patients (N=8) in comparison to healthy controls (N=7), at baseline and after 12 weeks oral CoQ supplementation. CoQ levels were similar among PAH and control individuals, and increased in all subjects with CoQ supplementation. PAH patients had higher CoQ levels than controls with supplementation, and a tendency to a higher reduced-to-oxidized CoQ ratio. Cardiac parameters improved with CoQ supplementation, although 6-minute walk distances and BNP levels did not significantly change. Consistent with improved mitochondrial synthetic function, hemoglobin increased and red cell distribution width (RDW) decreased in PAH patients with CoQ, while hemoglobin declined slightly and RDW did not change in healthy controls. In contrast, metabolic and redox parameters, including lactate, pyruvate and reduced or oxidized gluthathione, did not change in PAH patients with CoQ. In summary, CoQ improved hemoglobin and red cell maturation in PAH, but longer studies and/or higher doses with a randomized placebo-controlled controlled design are necessary to evaluate the clinical benefit of this simple nutritional supplement.
Graphical abstract
•Pulmonary arterial hypertension (PAH) is characterized by mitochondrial dysfunction.•Co-enzymeQ (CoQ) is important for mitochondria function.•CoQ supplementation improved heart function and red cell production in PAH.•The findings support the concept of mitochondrial-targeted therapies for PAH.
PMCID: PMC4143816  PMID: 25180165
Pulmonary hypertension; Mitochondria; Coenzyme Q; Hemoglobin; Heart failure; Metabolism
4.  Novel Therapeutic Approaches to Preserve the Right Ventricle 
Current heart failure reports  2013;10(1):12-17.
The right ventricle (RV) is increasingly recognized for its role in heart disease. In fact, RV function is a strong predictor of outcome in patients with cardiovascular disease. Although the focus in heart failure has been on the left ventricle (LV) recently the spotlight has been shifting to include the RV. The right and left ventricles have different embryological origins and respond differently to stressors and to therapies.
Newer therapies targeting the RV have been investigated in an attempt to improve right ventricular adaptation to cardiovascular diseases. In this review, we summarize the differences between the right and left ventricles and focus on novel therapies that target the RV.
PMCID: PMC3575635  PMID: 23065390
Right ventricle; heart failure; pulmonary hypertension; right ventricle hypertrophy
5.  Clinical characterization and survival of patients with borderline elevation in pulmonary artery pressure 
Pulmonary Circulation  2013;3(4):916-925.
Normal resting mean pulmonary artery pressure (PAP) is 8–20 mmHg. Pulmonary hypertension is defined as mean PAP of ≥25 mmHg. Borderline PAP levels of 21–24 mmHg are of unclear significance. We sought to determine the clinical characteristics and survival of subjects with mean PAP of 21–24 mmHg. We examined 1,491 patients enrolled in the Cleveland Clinic Pulmonary Hypertension Registry between February 1990 and May 2012 with baseline right heart catheterization. The relationship between PAP and all-cause mortality was assessed by Cox models and a tree-based analysis. Sixty-three patients had borderline PAP (underlying conditions: 12 left heart disease, 20 respiratory disease, 17 connective-tissue disease, 4 others, and 10 none). We then compared 3 groups: borderline PAP without heart or lung disease (), normal PAP without heart or lung disease (), and category 1 pulmonary arterial hypertension (PAH; ). Borderline-PAP patients had levels of hemodynamic and functional compromise between those for normal-PAP patients and those for patients with PAH. Borderline PAP was associated with increased mortality compared to normal PAP (hazard ratio: 4.03 [95% confidence interval: 0.78–20.80], ). A tree-based analysis demonstrated almost identical cut points in mean PAP (≤20, 21–26, and ≥27 mmHg) associated with differential survival (). Connective-tissue disease and an elevated transpulmonary gradient were predictors of worse survival in the borderline-PAP population. Borderline PAP elevation is associated with decreased survival, particularly in the context of connective-tissue disease and an elevated transpulmonary gradient.
PMCID: PMC4070822  PMID: 25006408
pulmonary artery pressure; pulmonary hypertension; pulmonary heart disease; survival
6.  Bone marrow–derived vascular modulatory cells in pulmonary arterial hypertension 
Pulmonary Circulation  2013;3(4):781-791.
Hematopoiesis and vascular homeostasis are closely linked to each other via subsets of circulating bone marrow–derived cells with potent activity to repair endothelial injury and promote angiogenesis. As a consequence, abnormalities in hematopoiesis will eventually affect vascular health. Pulmonary arterial hypertension (PAH) is a vascular disease characterized by severe remodeling of the pulmonary artery wall. Over the past decade, circulating hematopoietic cells have been assigned an increasing role in the remodeling, such that these cells have been used in new therapeutic strategies. More recently, research has been extended to the bone marrow where these cells originate to identify abnormalities in hematopoiesis that may underlie PAH. Here, we review the current literature and identify gaps in knowledge of the myeloid effects on PAH.
PMCID: PMC4070843  PMID: 25006394
7.  High Levels of Zinc-Protoporphyrin Identify Iron Metabolic Abnormalities in Pulmonary Arterial Hypertension 
Iron homeostasis influences the development of pulmonary arterial hypertension (PAH) associated with hypoxia or hematologic disorders. To investigate whether severity of idiopathic PAH (IPAH) is impacted by alterations in iron metabolism, we assessed iron metabolic markers, including levels of Zinc-protoporphyrin (Zn-pp), transferrin receptor, and red blood cell numbers and morphology in IPAH, associated PAH (APAH) and sleep apnea induced pulmonary hypertension (PH) patients in comparison to healthy controls and asthmatics. Despite similarly normal measures of iron metabolism, Zn-pp levels in IPAH and sleep apnea patients were elevated ~2-fold, indicating deficient iron incorporation to form heme and levels were closely related to measures of disease severity. Consistent with high Zn-PP, PAH patients had increased red cell distribution width (RDW). In an expanded cohort including patients with IPAH and familial disease (FPAH) the RDW was validated and related to clinical parameters of severity, including pulmonary artery pressures and 6 minute walk distances. These results reveal an increased prevalence of subclinical functional iron deficiency in primary forms of PAH that is quantitatively related to disease severity. This suggests that altered iron homeostasis influences disease progression and demonstrates the importance of closely monitoring iron status in PAH patients.
PMCID: PMC3575639  PMID: 21884511
8.  Loss of alveolar membrane diffusing capacity and pulmonary capillary blood volume in pulmonary arterial hypertension 
Respiratory Research  2013;14(1):6.
Reduced gas transfer in patients with pulmonary arterial hypertension (PAH) is traditionally attributed to remodeling and progressive loss of pulmonary arterial vasculature that results in decreased capillary blood volume available for gas exchange.
We tested this hypothesis by determination of lung diffusing capacity (DL) and its components, the alveolar capillary membrane diffusing capacity (Dm) and lung capillary blood volume (Vc) in 28 individuals with PAH in comparison to 41 healthy individuals, and in 19 PAH patients over time. Using single breath simultaneous measure of diffusion of carbon monoxide (DLCO) and nitric oxide (DLNO), DL and Dm were respectively determined, and Vc calculated. Dm and Vc were evaluated over time in relation to standard clinical indicators of disease severity, including brain natriuretic peptide (BNP), 6-minute walk distance (6MWD) and right ventricular systolic pressure (RVSP) by echocardiography.
Both DLCO and DLNO were reduced in PAH as compared to controls and the lower DL in PAH was due to loss of both Dm and Vc (all p < 0.01). While DLCO of PAH patients did not change over time, DLNO decreased by 24 ml/min/mmHg/year (p = 0.01). Consequently, Dm decreased and Vc tended to increase over time, which led to deterioration of the Dm/Vc ratio, a measure of alveolar-capillary membrane functional efficiency without changes in clinical markers.
The findings indicate that lower than normal gas transfer in PAH is due to loss of both Dm and Vc, but that deterioration of Dm/Vc over time is related to worsening membrane diffusion.
PMCID: PMC3560152  PMID: 23339456
Membrane diffusion; Pulmonary arterial hypertension; Lung capillary blood volume
9.  Pulmonary Gas Transfer Related to Markers of Angiogenesis during the Menstrual Cycle 
Gas transfer in the female lung varies over the menstrual cycle in parallel with the cyclic angiogenesis that occurs in the uterine endometrium. Given that vessels form and regress in the uterus under the control of hormones, angiogenic factors and pro-angiogenic circulating bone marrow-derived progenitor cells, we tested the possibility that variation in pulmonary gas transfer over the menstrual cycle is related to a systemic cyclic pro-angiogenic state that influences lung vascularity. Women were evaluated over the menstrual cycle with weekly measures of lung diffusing capacity and its components, the pulmonary vascular capillary bed and membrane diffusing capacity, and their relation to circulating CD34+CD133+ progenitor cells, hemoglobin, factors affecting hemoglobin binding affinity, and pro-angiogenic factors. Lung diffusing capacity varied over the menstrual cycle, reaching a nadir during the follicular phase following menses. The decline in lung diffusing capacity was accounted for by ~25% decrease in pulmonary capillary blood volume. In parallel, circulating CD34+CD133+ progenitor cells decreased by ~24%, and were directly related to angiogenic factors, and to lung diffusing capacity and pulmonary capillary blood volume. The finding of greater number of lung microvessels in ovariectomized female mice receiving estrogen as compared to placebo verified that pulmonary vascularity is influenced by hormonal changes. These findings suggest that angiogenesis in the lungs may participate in the cyclic changes in gas transfer that occur over the menstrual cycle.
PMCID: PMC3038173  PMID: 17717117
Gas transfer; endothelial progenitor cell; angiogenesis; menstrual cycle
10.  Ventricular Geometry, Strain, and Rotational Mechanics in Pulmonary Hypertension 
Circulation  2010;121(2):259-266.
We tested the hypothesis that right ventricular (RV) pressure overload affects RV function, and further influences left ventricular (LV) geometry that adversely affects LV twist mechanics and segmental function.
Methods and Results
Echocardiographic images were prospectively acquired in 44 (46±12 years; 82%F) patients with evidence of pulmonary hypertension (PH) (estimated pulmonary systolic pressure [PASP] =71±23 mmHg) and in 44 age and gender-matched healthy subjects. Patients with intrinsic LV diseases were excluded. RV lateral wall (RVLAT) longitudinal strain (LS) and interventricular septal (IVS) LS were reduced in PH group compared with controls (-15.9±7.6% vs.-25.5±6.1%, p<0.001 and -17.3±4.4% vs.-20.2±3.9%, p=0.002, respectively), while LV lateral wall (LVLAT) LS was preserved. RVLAT and IVS LS, but not LVLAT LS, correlated with PASP(r=0.56, p<0.01; r=0.32, p<0.01) and LV eccentricity index (LVEI) (r=0.57, p<0.01; r=0.57, p<0.01). IVS and LVLAT circumferential strains (CS) were both reduced in the PH group. Although IVS CS and LVLAT CS correlated with PASP and LVEI, after adjusting CS for LVEI, differences between groups persisted for IVS CS (p<0.01) but not LVLAT CS (p=0.09). LV torsion was decreased in patients with PH compared with controls (9.6±4.9° vs. 14.7±4.9°, p<0.001). LV torsion inversely correlated with PASP (r=-0.39, p<0.01) and LVEI (r=-0.3, p<0.01). LV untwisting rates were similar in both groups (p=0.7).
Chronic RV pressure overload directly affects RV longitudinal systolic deformation. RV pressure overload further influences IVS and LV geometry, which impairs LV torsion and segmental LS and CS, more for the IVS than the free wall of the LV.
PMCID: PMC2846516  PMID: 20048214
Torsion; pulmonary hypertension; strain; echocardiography
11.  Effects of the Menstrual Cycle on Lung Function Variables in Women with Asthma 
Rationale: Angiogenesis is a defining pathologic feature of airway remodeling and contributes to asthma severity. Women experience changes in asthma control over the menstrual cycle, a time when vessels routinely form and regress under the control of angiogenic factors. One vital function modulated over the menstrual cycle in healthy women is gas transfer, and this has been related to angiogenesis and cyclic expansion of the pulmonary vascular bed.
Objectives: We hypothesized that changes in gas transfer and the pulmonary vascular bed occur in women with asthma over the menstrual cycle and are associated with worsening airflow obstruction.
Methods: Twenty-three women, 13 with asthma and 10 healthy control subjects, were evaluated over the menstrual cycle with weekly measures of spirometry, gas transfer, nitric oxide, hemoglobin, factors affecting hemoglobin binding affinity, and proangiogenic factors.
Measurements and Main Results: Airflow and lung diffusing capacity varied over the menstrual cycle with peak levels during menses that subsequently declined to nadir in early luteal phase. In contrast to healthy women, changes in lung diffusing capacity (DlCO) were associated with changes in membrane diffusing capacity and DlCO was not related to proangiogenic factors. DlCO did not differ between the two groups, although methemoglobin and carboxyhemoglobin were higher in women with asthma than in healthy women.
Conclusions: Women with asthma experience cyclic changes in airflow as well as gas transfer and membrane diffusing capacity supportive of a hormonal effect on lung function.
PMCID: PMC2731807  PMID: 19520904
gas transfer; angiogenesis; asthma; menstrual cycle; proangiogenic progenitor cell

Results 1-11 (11)