bluuebunny/crossref_metadata_2025 huggingface dataset:
Mitochondrial function and increased convective O2 transport: implications for the assessment of mitochondrial respiration in vivo
Authors: Layec Gwenael , Haseler Luke J. , Trinity Joel D. , Hart Corey R. , Liu Xin , Le Fur Yann , Jeong Eun-Kee , Richardson Russell S.
Published: June 2013

Although phosphorus magnetic resonance spectroscopy (31P-MRS)-based evidence suggests that in vivo peak mitochondrial respiration rate in young untrained adults is limited by the intrinsic mitochondrial capacity of ATP synthesis, it remains unknown whether a large, locally targeted increase in convective O2 delivery would alter this interpretation. Consequently, we examined the effect of superimposing reactive hyperemia (RH), induced by a period of brief ischemia during the last minute of exercise, on oxygen delivery and mitochondrial function in the calf muscle of nine young adults compared with free-flow conditions (FF). To this aim, we used an integrative experimental approach combining 31P-MRS, Doppler ultrasound imaging, and near-infrared spectroscopy. Limb blood flow [area under the curve (AUC), 1.4 ± 0.8 liters in FF and 2.5 ± 0.3 liters in RH, P < 0.01] and convective O2 delivery (AUC, 0.30 ± 0.16 liters in FF and 0.54 ± 0.05 liters in RH, P < 0.01), were significantly increased in RH compared with FF. RH was also associated with significantly higher capillary blood flow ( P < 0.05) and faster tissue reoxygenation mean response times (70 ± 15 s in FF and 24 ± 15 s in RH, P < 0.05). This resulted in a 43% increase in estimated peak mitochondrial ATP synthesis rate (29 ± 13 mM/min in FF and 41 ± 14 mM/min in RH, P < 0.05) whereas the phosphocreatine (PCr) recovery time constant in RH was not significantly different ( P = 0.22). This comprehensive assessment of local skeletal muscle O2 availability and utilization in untrained subjects reveals that mitochondrial function, assessed in vivo by 31P-MRS, is limited by convective O2 delivery rather than an intrinsic mitochondrial limitation.
The influence of training status, age, and muscle fiber type on cycling efficiency and endurance performance
Authors: Hopker James G. , Coleman Damian A. , Gregson Hannah C. , Jobson Simon A. , Von der Haar Tobias , Wiles Jonathan , Passfield Louis
Published: June 2013

The purpose of this study was to assess the influence of age, training status, and muscle fiber-type distribution on cycling efficiency. Forty men were recruited into one of four groups: young and old trained cyclists, and young and old untrained individuals. All participants completed an incremental ramp test to measure their peak O2uptake, maximal heart rate, and maximal minute power output; a submaximal test of cycling gross efficiency (GE) at a series of absolute and relative work rates; and, in trained participants only, a 1-h cycling time trial. Finally, all participants underwent a muscle biopsy of their right vastus lateralis muscle. At relative work rates, a general linear model found significant main effects of age and training status on GE ( P < 0.01). The percentage of type I muscle fibers was higher in the trained groups ( P < 0.01), with no difference between age groups. There was no relationship between fiber type and cycling efficiency at any work rate or cadence combination. Stepwise multiple regression indicated that muscle fiber type did not influence cycling performance ( P > 0.05). Power output in the 1-h performance trial was predicted by average O2uptake and GE, with standardized β-coefficients of 0.94 and 0.34, respectively, although some mathematical coupling is evident. These data demonstrate that muscle fiber type does not affect cycling efficiency and was not influenced by the aging process. Cycling efficiency and the percentage of type I muscle fibers were influenced by training status, but only GE at 120 revolutions/min was seen to predict cycling performance.
Hypertrophy in the cervical muscles and thoracic discs in bed rest?
Authors: Belavý Daniel L. , Miokovic Tanja , Armbrecht Gabriele , Felsenberg Dieter
Published: June 2013

The impact of prolonged bed rest on the cervical and upper thoracic spine is unknown. In the 2nd Berlin BedRest Study (BBR2-2), 24 male subjects underwent 60-day bed rest and performed either no exercise, resistive exercise, or resistive exercise with whole body vibration. Subjects were followed for 2 yr after bed rest. On axial cervical magnetic resonance images from the skull to T3, the volumes of the semispinalis capitis, splenius capitis, spinalis cervicis, longus capitis, longus colli, levator scapulae, sternocleidomastoid, middle and posterior scalenes, and anterior scalenes were measured. Disc height, anteroposterior width, and volume were measured from C2/3to T6/7on sagittal images. The volume of all muscles, with the exception of semispinalis capitis, increased during bed rest ( P < 0.025). There were no significant differences between the groups for changes in the muscles. Increased upper and midthoracic spine disc height and volume ( P < 0.001) was seen during bed rest, and disc height increases persisted at least 6 mo after bed rest. Increases in thoracic disc height were greater ( P = 0.003) in the resistive vibration exercise group than in control. On radiological review, two subjects showed new injuries to the mid-lower thoracic spine. One of these subjects reported a midthoracic pain incident during maximal strength testing before bed rest and the other after countermeasure exercise on day 3 of bed rest. We conclude that bed rest is associated with increased disc size in the thoracic region and increases in muscle volume at the neck. The exercise device needs to be modified to ensure that load is distributed in a more physiological fashion.
Effects of lung inflation on airway heterogeneity during histaminergic bronchoconstriction
Authors: Kaczka David W. , Mitzner Wayne , Brown Robert H.
Published: June 2013

Lung inflation has been shown to dilate airways by altering the mechanical equilibrium between opposing airway and parenchymal forces. However, it is not known how heterogeneously such dilation occurs throughout the airway tree. In six anesthetized dogs, we measured the diameters of five to six central airway segments using high-resolution computed tomography, along with respiratory input impedance ( Z rs) during generalized aerosol histamine challenge, and local histamine challenge in which the agonist was instilled directly onto the epithelia of the imaged central airways. Airway diameters and Z rs were measured at 12 and 25 cmH2O. The Z rs spectra were fitted with a model that incorporated continuous distributions of airway resistances. Airway heterogeneity was quantified using the coefficient of variation for predefined airway distribution functions. Significant reductions in average central airway diameter were observed at 12 cmH2O for both aerosolized and local challenges, along with significant increases upon inflation to 25 cmH2O. No significant differences were observed for the coefficient of variation of airway diameters under any condition. Significant increases in effective airway resistance as measured by Z rs were observed only for the aerosolized challenge at 12 cmH2O, which was completely reversed upon inflation. We conclude that the lung periphery may be the most dominant contributor to increases in airway resistance and tissue elastance during bronchoconstriction induced by aerosolized histamine. However, isolated constriction of only a few central airway segments may also affect tissue stiffness via interdependence with their surrounding parenchyma.
Relationship between Carbon Stock and Plant Biodiversity in Collaborative Forests in Terai, Nepal
Authors: Mandal Ram Asheshwar , Dutta Ishwar Chandra , Jha Pramod Kumar , Karmacharya Siddhibir
Published: July 2013

Reducing emission from deforestation and forest degradation (REDD+) programme has prime concern to carbon stock enhancement rather than biodiversity conservation. Participatory managed forest has been preparing to get benefit under this programme, and collaborative forest is one of them in Nepal. Hence, this research is intended to assess the relationship between carbon stock and biodiversity. Three collaborative forests (CFMs) were selected as study sites in Mahottari district, Nepal. Altogether 96 sample plots were established applying stratified random sampling. The plot size for tree was 20 m × 25 m. Similarly, other concentric plots were established. Diameter at breast height (DBH) and height were measured, species were counted, and soil samples were collected from 0–0.1, 0.1–0.3, and 0.3–0.6 m depths. The biomass was calculated using equation of Chave et al. and converted into carbon, soil carbon was analyzed in laboratory, and plant biodiversity was calculated. Then, relation between carbon stock and biodiversity was developed. Estimated carbon stocks were 197.10, 222.58, and 274.66 ton ha−1in Banke-Maraha, Tuteshwarnath, and Gadhanta-Bardibas CFMs, respectively. The values of Shannon-Wiener Biodiversity Index ranged 2.21–2.33. Any significant relationship between carbon stock and biodiversity, and was not found hence REDD+ programme should emphasize on biodiversity conservation.
Visualized Characterization for Cerebral Response of Acupuncture Deqi: Paradox Underway
Authors: Yang Jie , Yang Ming-Xiao , Zeng Fang , Wu Xi , Chen Jiao , Liu Yan-Qin , Feng Yue , Liang Fan-Rong
Published: July 2013

Acupuncture as an oriental natural healing therapy with prolonged history has been extensively utilized in the management of great numbers of disorders. Deqi, a renowned acupuncture needling sensation, is profoundly regarded as the predictor and also the prerequisite of a preferable acupuncture treatment efficacy. Till now, there is still no consistency being reached towards the mechanism of acupuncture Deqi as a result of the discrepancy for publicly acknowledged evidence. Recent visualized research on Deqi using modern technologies has demonstrated possible central mechanism towards it. However, there is a conspicuous paradox underway in the research of cerebral response to acupuncture Deqi. This paper provided a view of up-to-date studies using visualized tools to characterize the brain response to acupuncture Deqi, such as functional magnetic resonance imaging (fMRI) and positron emission tomography/computed tomography (PET/CT). The paradox was extruded to highlight certain reasons from a TCM view. It is hypothesized that acupoints located at different dermal sites, state of participant, and needling manipulation can all contribute to the current paradox. Hence, further studies on acupuncture Deqi should pay more attention to the strategy of experiment design with generalized measurement, valid sham control methods, and more to subjects in diseased condition.
Candidate Tumor Suppressor and pVHL Partner Jade-1 Binds and Inhibits AKT in Renal Cell Carcinoma
Authors: Zeng Liling , Bai Ming , Mittal Amit K. , El-Jouni Wassim , Zhou Jing , Cohen David M. , Zhou Mina I. , Cohen Herbert T.
Published: July 2013

The von Hippel–Lindau (VHL) tumor suppressor pVHL is lost in the majority of clear-cell renal cell carcinomas (RCC). Activation of the PI3K/AKT/mTOR pathway is also common in RCC, with PTEN loss occurring in approximately 30% of the cases, but other mechanisms responsible for activating AKT at a wider level in this setting are undefined. Plant homeodomain protein Jade-1 (PHF17) is a candidate renal tumor suppressor stabilized by pVHL. Here, using kinase arrays, we identified phospho-AKT1 as an important target of Jade-1. Overexpressing or silencing Jade-1 in RCC cells increased or decreased levels of endogenous phospho-AKT/AKT1. Furthermore, reintroducing pVHL into RCC cells increased endogenous Jade-1 and suppressed endogenous levels of phospho-AKT, which colocalized with and bound to Jade-1. The N-terminus of Jade-1 bound both the catalytic domain and the C-terminal regulatory tail of AKT, suggesting a mechanism through which Jade-1 inhibited AKT kinase activity. Intriguingly, RCC precursor cells where Jade-1 was silenced exhibited an increased capacity for AKT-dependent anchorage-independent growth, in support of a tumor suppressor function for Jade-1 in RCC. In support of this concept, an in silico expression analysis suggested that reduced Jade-1 expression is a poor prognostic factor in clear-cell RCC that is associated with activation of an AKT1 target gene signature. Taken together, our results identify 2 mechanisms for Jade-1 fine control of AKT/AKT1 in RCC, through loss of pVHL, which decreases Jade-1 protein, or through attenuation in Jade-1 expression. These findings help explain the pathologic cooperativity in clear-cell RCC between PTEN inactivation and pVHL loss, which leads to decreased Jade-1 levels that superactivate AKT. In addition, they prompt further investigation of Jade-1 as a candidate biomarker and tumor suppressor in clear-cell RCC. Cancer Res; 73(17); 5371–80. ©2013 AACR.
Acquired Expression of NFATc1 Downregulates E-Cadherin and Promotes Cancer Cell Invasion
Authors: Oikawa Tsukasa , Nakamura Atsuko , Onishi Nobuyuki , Yamada Taketo , Matsuo Koichi , Saya Hideyuki
Published: June 2013

NFATc1 is a transcription factor that regulates T-cell development, osteoclastogenesis, and macrophage function. Given that T cells, osteoclasts, and macrophages in the tumor microenvironment are thought to modulate tumor progression, tumor cells may acquire NFATc1 expression through fusion with these NFATc1-expressing normal cells. We here revealed that a small proportion of tumor cells in human carcinoma specimens expressed NFATc1. To investigate the consequences of NFATc1 acquisition by tumor cells, we established A549 and MCF7 cell lines expressing a constitutively active form of NFATc1 (NFATc1CA) in an inducible manner. The expression of NFATc1CA promoted cancer cell invasion in association with changes in cell morphology. Analysis of gene expression and RNA interference experiments revealed that NFATc1CA suppressed E-cadherin expression by upregulating the transcriptional repressors Snail and Zeb1 in a manner independent of TGF-β signaling. Induced expression of NFATc1CA also downregulated E-cadherin expression and increased invasive activity in tumor xenografts in vivo. Our results thus suggest that the acquisition of NFATc1 expression contributes to tumor progression. Cancer Res; 73(16); 5100–9. ©2013 AACR.
Pleiotropy between Genetic Markers of Obesity and Risk of Prostate Cancer
Authors: Edwards Todd L. , Giri Ayush , Motley Saundra , Duong Wynne , Fowke Jay H.
Published: June 2013

Background: To address inconsistent findings of obesity and prostate cancer risk, we analyzed the association between prostate cancer and genetic markers of obesity and metabolism.

Methods: Analyses included 176,520 single-nucleotide polymorphisms (SNP) associated with 23 metabolic traits. We examined the association between SNPs and prostate cancer in 871 cases and 906 controls, including 427 high-grade cases with Gleason ≥ 7. Genetic risk scores (GRS) for body mass index (BMI) and waist-to-hip ratio (WHR) were also created by summing alleles associated with increasing BMI or WHR.

Results: Prostate cancer was associated with five loci, including cyclin M2, with P values less than 1 × 10−4. In addition, the WHR GRS was associated with high-grade prostate cancer versus controls [OR, 1.05; 95% confidence interval (CI), 1.00–1.11; P = 0.048] and high-grade prostate cancer versus low-grade prostate cancer (OR, 1.07; 95% CI, 1.01–1.13; P = 0.03). None of these findings exceeds the threshold for significance after correction for multiple testing.

Conclusions: Variants in genes known to be associated with metabolism and obesity may be associated with prostate cancer. We show evidence for pleiotropy between WHR GRS and prostate cancer grade. This finding is consistent with the function of several WHR genes and previously described relationships with cancer traits.

Impact: Limitations in standard obesity measures suggest alternative characterizations of obesity may be needed to understand the role of metabolic dysregulation in prostate cancer. The underlying genetics of WHR or other Metabochip SNPs, while not statistically significant beyond multiple testing thresholds within our sample size, support the metabolic hypothesis of prostate carcinogenesis and warrant further investigation in independent samples. Cancer Epidemiol Biomarkers Prev; 22(9); 1538–46. ©2013 AACR.
PTGS2 (Cyclooxygenase-2) Expression and Survival among Colorectal Cancer Patients: A Systematic Review
Authors: Kunzmann Andrew T. , Murray Liam J. , Cardwell Chris R. , McShane Charlene M. , McMenamin Úna C. , Cantwell Marie M.
Published: June 2013

Background: Studies have examined whether tumor expression of PTGS2 (also known as COX-2), an enzyme inhibited by nonsteroidal anti-inflammatory drugs such as aspirin, is associated with prognosis in patients with colorectal cancer. However, results to date have been mixed.

Methods: Using terms for PTGS2 and colorectal cancer, the Medline, Embase, and Web of Science databases were systematically searched for studies published, in any language, until December 2011. Random effects meta-analyses were used to calculate pooled HRs [95% confidence intervals (CI)] for the association between PTGS2 expression and tumor recurrence, colorectal cancer–specific survival, and overall survival.

Results: In total, 29 studies, which had prognostic data on 5,648 patients, met the inclusion criteria. PTGS2-positive patients were at an increased risk of tumor recurrence (n = 9 studies; HR, 2.79; 95% CI, 1.76–4.41; P < 0.001) and had poorer colorectal cancer–specific survival (n = 7; HR, 1.36; 95% CI, 1.02–1.82; P = 0.04). However, there was funnel plot asymmetry, possibly due to publication bias, for the association with cancer-specific survival but less so for recurrence. PTGS2 expression was not associated with overall survival [(n = 16; pooled unadjusted HR, 1.30; 95% CI, 0.94–1.79; P = 0.11) and (n = 9; pooled adjusted HR, 1.02; 95% CI, 0.72–1.45; P = 0.91)].

Conclusions: PTGS2 expression was associated with an increased risk of tumor recurrence and poorer colorectal cancer–specific survival but not overall survival among patients with colorectal cancer. However, confounding by tumor characteristics such as tumor stage seems likely.

Impact: There is insufficient evidence to recommend PTGS2 expression as a prognostic marker in patients with colorectal cancer. Furthermore, studies providing adjusted results are required. Cancer Epidemiol Biomarkers Prev; 22(9); 1490–7. ©2013 AACR.
Ki67 Measured after Neoadjuvant Chemotherapy for Primary Breast Cancer
Authors: von Minckwitz Gunter , Schmitt Wolfgang D. , Loibl Sibylle , Müller Berit M. , Blohmer Jens U. , Sinn Bruno V. , Eidtmann Holger , Eiermann Wolfgang , Gerber Bernd , Tesch Hans , Hilfrich Jörn , Huober Jens , Fehm Tanja , Barinoff Jana , Rüdiger Thomas , Erbstoesser Erhard , Fasching Peter A. , Karn Thomas , Müller Volkmar , Jackisch Christian , Denkert Carsten
Published: June 2013

Purpose: The value of Ki67 measured on residual disease after neoadjuvant chemotherapy is not sufficiently described.

Experimental Design: Participants of the GeparTrio study with primary breast cancer randomly received neoadjuvant response-guided [8 cycles TAC (docetaxel/doxorubicin/cyclophosphamide) in responding and TAC-NX (vinorelbine/capecitabine) in nonresponding patients] or conventional (6 cycles TAC) chemotherapy according to interim response assessment. Ki-67 levels were centrally measured immunohistochemically after neoadjuvant treatment if tumor tissue was available. Here, we analyze 1,151 patients having a pathologic complete response (pCR; n, 484), or residual disease with low (0–15%), intermediate (15.1–35%), or high (35.1–100%) posttreatment Ki67 levels in 488, 77, and 102 patients, respectively.

Results: Patients with high posttreatment Ki67 levels showed higher risk for disease relapse (P < 0.0001) and death (P < 0.0001) compared with patients with low or intermediate Ki67 levels. Patients with low Ki67 levels showed a comparable outcome to patients with a pCR (P = 0.211 for disease-free and P = 0.779 for overall survival). Posttreatment Ki67 levels provided more prognostic information than pretreatment Ki67 levels or changes of Ki67 from pre- to posttreatment. Information on pCR plus posttreatment Ki67 levels surmount the prognostic information of pCR alone in hormone–receptor-positive disease [hazard ratios (HR), 1.82–5.88] but not in hormone–receptor-negative disease (HR: 0.61–1.73). Patients with conventional and response-guided treatment did not show a different distribution of posttreatment Ki67 (P = 0.965).

Conclusions: Posttreatment Ki67 levels provide prognostic information for patients with hormone–receptor-positive breast cancer and residual disease after neoadjuvant chemotherapy. Levels were not prognostic for outcome after response-guided chemotherapy. High posttreatment Ki67 indicates the need for innovative postneoadjuvant treatments. Clin Cancer Res; 19(16); 4521–31. ©2013 AACR.
A Novel Aldehyde Dehydrogenase-3 Activator (Alda-89) Protects Submandibular Gland Function from Irradiation without Accelerating Tumor Growth
Authors: Xiao Nan , Cao Hongbin , Chen Che-Hong , Kong Christina S. , Ali Rehan , Chan Cato , Sirjani Davud , Graves Edward , Koong Albert , Giaccia Amato , Mochly-Rosen Daria , Le Quynh-Thu
Published: June 2013

Purpose: To determine the effect of Alda-89 (an ALDH3 activitor) on (i) the function of irradiated (radiotherapy) submandibular gland (SMG) in mice, (ii) its toxicity profile, and (iii) its effect on the growth of head and neck cancer (HNC) in vitro and in vivo.

Experimental Design: Adult mice were infused with Alda-89 or vehicle before, during, and after radiotherapy. Saliva secretion was monitored weekly. Hematology, metabolic profile, and postmortem evaluation for toxicity were examined at the time of sacrifice. Alda-89 or vehicle was applied to HNC cell lines in vitro, and severe combined immunodeficient (SCID) mice transplanted with HNC in vivo with or without radiation; HNC growth was monitored. The ALDH3A1 and ALDH3A2 protein expression was evaluated in 89 patients with HNC and correlated to freedom from relapse (FFR) and overall survival (OS).

Results: Alda-89 infusion significantly resulted in more whole saliva production and a higher percentage of preserved acini after radiotherapy compared with vehicle control. There was no difference in the complete blood count, metabolic profile, and major organ morphology between the Alda-89 and vehicle groups. Compared with vehicle control, Alda-89 treatment neither accelerated HNC cell proliferation in vitro, nor did it affect tumor growth in vivo with or without radiotherapy. Higher expression of ALDH3A1 or ALDH3A2 was not significantly associated with worse FFR or OS in either human papillomavirus (HPV)-positive or HPV-negative group.

Conclusion: Alda-89 preserves salivary function after radiotherapy without affecting HNC growth or causing measurable toxicity in mice. It is a promising candidate to mitigate radiotherapy-related xerostomia. Clin Cancer Res; 19(16); 4455–64. ©2013 AACR.
Development and Preclinical Characterization of a Humanized Antibody Targeting CXCL12
Authors: Zhong Cuiling , Wang Jianyong , Li Bing , Xiang Hong , Ultsch Mark , Coons Mary , Wong Terence , Chiang Nancy Y. , Clark Suzy , Clark Robyn , Quintana Leah , Gribling Peter , Suto Eric , Barck Kai , Corpuz Racquel , Yao Jenny , Takkar Rashi , Lee Wyne P. , Damico-Beyer Lisa A. , Carano Richard D. , Adams Camellia , Kelley Robert F. , Wang Weiru , Ferrara Napoleone
Published: June 2013

Purpose: Our goal was to develop a potent humanized antibody against mouse/human CXCL12. This report summarized its in vitro and in vivo activities.

Experimental Design: Cell surface binding and cell migration assays were used to select neutralizing hamster antibodies, followed by testing in several animal models. Monoclonal antibody (mAb) 30D8 was selected for humanization based on its in vitro and in vivo activities.

Results: 30D8, a hamster antibody against mouse and human CXCL12α, CXCL12β, and CXCL12γ, was shown to dose-dependently block CXCL12α binding to CXCR4 and CXCR7, and CXCL12α-induced Jurkat cell migration in vitro. Inhibition of primary tumor growth and/or metastasis was observed in several models. 30D8 alone significantly ameliorated arthritis in a mouse collagen-induced arthritis model (CIA). Combination with a TNF-α antagonist was additive. In addition, 30D8 inhibited 50% of laser-induced choroidal neovascularization (CNV) in mice. Humanized 30D8 (hu30D8) showed similar in vitro and in vivo activities as the parental hamster antibody. A crystal structure of the hu30D8 Fab/CXCL12α complex in combination with mutational analysis revealed a “hot spot” around residues Asn44/Asn45 of CXCL12α and part of the RFFESH region required for CXCL12α binding to CXCR4 and CXCR7. Finally, hu30D8 exhibited fast clearance in cynomolgus monkeys but not in rats.

Conclusion: CXCL12 is an attractive target for treatment of cancer and inflammation-related diseases; hu30D8 is suitable for testing this hypothesis in humans. Clin Cancer Res; 19(16); 4433–45. ©2013 AACR.
The Potential Role of miR-451 in Cancer Diagnosis, Prognosis, and Therapy
Authors: Pan Xuan , Wang Rui , Wang Zhao-Xia
Published: June 2013

MicroRNAs (miRNA) are small noncoding RNAs that converge to maintain an intrinsic balance of various processes, including cell proliferation, differentiation, and apoptosis. Recent research efforts have been devoted to translating these basic discoveries into applications that could improve the early diagnosis and therapeutic outcome of patients with cancer. Early studies have shown that miRNA-451 (miR-451) is widely dysregulated in human cancers and plays a critical role in tumorigenesis and tumor progression. In this review, we summarize the potential use of miR-451 for cancer diagnosis, prognosis, and treatment. In addition, we discuss the possible mechanisms of miR-451 dysregulation and future challenges in development of miR-451 as a noninvasive biomarker and a potential therapeutic target in human cancers. Mol Cancer Ther; 12(7); 1153–62. ©2013 AACR.
Dual Inhibition of PI3K and mTOR Mitigates Compensatory AKT Activation and Improves Tamoxifen Response in Breast Cancer
Authors: Chen Xiaosong , Zhao Meizhong , Hao Mingang , Sun Xueqing , Wang Jinglong , Mao Yan , Zu Lidong , Liu Junjun , Shen Yandong , Wang Jianhua , Shen Kunwei
Published: June 2013

Everolimus, an mTOR inhibitor, showed great clinical efficacy in combination with tamoxifen, letrozole, or exemestane for the treatment of estrogen receptor-positive (ER+) breast cancer. However, its antitumor activity was shown to be compromised by a compensatory process involving AKT activation. Here, it was determined whether combining an additional PI3K inhibitor can reverse this phenomenon and improve treatment efficacy. In breast cancer cells (MCF-7 and BT474), everolimus inhibited the mTOR downstream activity by limiting phosphorylation of p70S6K and 4EBP1, which resulted in p-Ser473-AKT activation. However, addition of a LY294002, a PI3K inhibitor, to tamoxifen and everolimus treatment improved the antitumor effect compared with tamoxifen alone or the other two agents in combination. Moreover, LY294002 suppressed the activity of the PI3K/AKT/mTOR axis and mitigated the p-Ser473-AKT activation feedback loop in both cell lines. Critically, this combination scheme also significantly inhibited the expression of HIF-1a, an angiogenesis marker, under hypoxic conditions and reduced blood vessel sprout formation in vitro. Finally, it was shown that the three-agent cocktail had the greatest efficacy in inhibiting MCF-7 xenograft tumor growth and angiogenesis. Taken together, these results suggest that inhibition of PI3K and mTOR may further improve therapy in ER+ breast cancer cells.

Implications: Combinatorial inhibition of the PI3K/AKT/mTOR signaling axis may enhance endocrine-based therapy in breast cancer. Mol Cancer Res; 11(10); 1269–78. ©2013 AACR.
Liver ABCA1 Deletion in LDLrKO Mice Does Not Impair Macrophage Reverse Cholesterol Transport or Exacerbate Atherogenesis
Authors: Bi Xin , Zhu Xuewei , Duong MyNgan , Boudyguina Elena Y. , Wilson Martha D. , Gebre Abraham K. , Parks John S.
Published: June 2013

Objective—

Hepatic ATP binding cassette transporter A1 (ABCA1) expression is critical for maintaining plasma high-density lipoprotein (HDL) concentrations, but its role in macrophage reverse cholesterol transport and atherosclerosis is not fully understood. We investigated atherosclerosis development and reverse cholesterol transport in hepatocyte-specific ABCA1 knockout (HSKO) mice in the low-density lipoprotein (LDL) receptor KO (LDLrKO) C57BL/6 background.

Approach and Results—

Male and female LDLrKO and HSKO/LDLrKO mice were switched from chow at 8 weeks of age to an atherogenic diet (10% palm oil, 0.2% cholesterol) for 16 weeks. Chow-fed HSKO/LDLrKO mice had HDL concentrations 10% to 20% of LDLrKO mice, but similar very low-density lipoprotein and LDL concentrations. Surprisingly, HSKO/LDLrKO mice fed the atherogenic diet had significantly lower (40% to 60%) very low-density lipoprotein, LDL, and HDL concentrations (50%) compared with LDLrKO mice. Aortic surface lesion area and cholesterol content were similar for both genotypes of mice, but aortic root intimal area was significantly lower (20% to 40%) in HSKO/LDLrKO mice. Although macrophage
3
H-cholesterol efflux to apoB lipoprotein–depleted plasma was 24% lower for atherogenic diet–fed HSKO/LDLrKO versus LDLrKO mice, variation in percentage efflux among individual mice was <2-fold compared with a 10-fold variation in plasma HDL concentrations, suggesting that HDL levels, per se, were not the primary determinant of plasma efflux capacity. In vivo reverse cholesterol transport, resident peritoneal macrophage sterol content, biliary lipid composition, and fecal cholesterol mass were similar between both genotypes of mice.

Conclusions—

The markedly reduced plasma HDL pool in HSKO/LDLrKO mice is sufficient to maintain macrophage reverse cholesterol transport, which, along with reduced plasma very low-density lipoprotein and LDL concentrations, prevented the expected increase in atherosclerosis.
Smad2-Dependent Protease Nexin-1 Overexpression Differentiates Chronic Aneurysms From Acute Dissections of Human Ascending Aorta
Authors: Gomez Delphine , Kessler Ketty , Borges Luciano F. , Richard Benjamin , Touat Ziad , Ollivier Véronique , Mansilla Silvana , Bouton Marie-Christine , Alkoder Soleyman , Nataf Patrick , Jandrot-Perrus Martine , Jondeau Guillaume , Vranckx Roger , Michel Jean-Baptiste
Published: June 2013

Objective—

Tissue activation of proteolysis is involved in acute intramural rupture (dissections, acute ascending aortic dissection) and in progressive dilation (aneurysms, thoracic aneurysm of the ascending aorta) of human ascending aorta. The translational aim of this study was to characterize the regulation of antiproteolytic serpin expression in normal, aneurysmal, and dissecting aorta.

Approach and Results—

We explored expression of protease nexin-1 (PN-1) and plasminogen activator inhibitor-1 and their regulation by the Smad2 signaling pathway in human tissue and cultured vascular smooth muscle cells (VSMCs) of aneurysms (thoracic aneurysm of the ascending aorta; n=46) and acute dissections (acute ascending aortic dissection; n=10) of the ascending aorta compared with healthy aortas (n=10). Both PN-1 and plasminogen activator inhibitor-1 mRNA and proteins were overexpressed in medial tissue extracts and primary VSMC cultures from thoracic aneurysm of the ascending aorta compared with acute ascending aortic dissection and controls. Transforming growth factor-β induced increased PN-1 expression in control but not in aneurysmal VSMCs. PN-1 and plasminogen activator inhibitor-1 overexpression by aneurysmal VSMCs was associated with increased Smad2 binding on their promoters and, functionally, resulted in VSMC self-protection from plasmin-induced detachment and death. This phenomenon was restricted to aneurysms and not observed in acute dissections.

Conclusions—

These results demonstrate that epigenetically regulated PN-1 overexpression promotes development of an antiproteolytic VSMC phenotype and might favor progressive aneurysmal dilation, whereas absence of this counter-regulation in dissections would lead to acute wall rupture.
Elevated Levels of Circulating DNA and Chromatin Are Independently Associated With Severe Coronary Atherosclerosis and a Prothrombotic State
Authors: Borissoff Julian I. , Joosen Ivo A. , Versteylen Mathijs O. , Brill Alexander , Fuchs Tobias A. , Savchenko Alexander S. , Gallant Maureen , Martinod Kimberly , ten Cate Hugo , Hofstra Leonard , Crijns Harry J. , Wagner Denisa D. , Kietselaer Bas L.J.H.
Published: July 2013

Objective—

Aberrant neutrophil activation occurs during the advanced stages of atherosclerosis. Once primed, neutrophils can undergo apoptosis or release neutrophil extracellular traps. This extracellular DNA exerts potent proinflammatory, prothrombotic, and cytotoxic properties. The goal of this study was to examine the relationships among extracellular DNA formation, coronary atherosclerosis, and the presence of a prothrombotic state.

Approach and Results—

In a prospective, observational, cross-sectional cohort of 282 individuals with suspected coronary artery disease, we examined the severity, extent, and phenotype of coronary atherosclerosis using coronary computed tomographic angiography. Double-stranded DNA, nucleosomes, citrullinated histone H4, and myeloperoxidase–DNA complexes, considered in vivo markers of cell death and NETosis, respectively, were established. We further measured various plasma markers of coagulation activation and inflammation. Plasma double-stranded DNA, nucleosomes, and myeloperoxidase–DNA complexes were positively associated with thrombin generation and significantly elevated in patients with severe coronary atherosclerosis or extremely calcified coronary arteries. Multinomial regression analysis, adjusted for confounding factors, identified high plasma nucleosome levels as an independent risk factor of severe coronary stenosis (odds ratio, 2.14; 95% confidence interval, 1.26–3.63;
P
=0.005). Markers of neutrophil extracellular traps, such as myeloperoxidase–DNA complexes, predicted the number of atherosclerotic coronary vessels and the occurrence of major adverse cardiac events.

Conclusions—

Our report provides evidence demonstrating that markers of cell death and neutrophil extracellular trap formation are independently associated with coronary artery disease, prothrombotic state, and occurrence of adverse cardiac events. These biomarkers could potentially aid in the prediction of cardiovascular risk in patients with chest discomfort.
Endothelial Cell Sensing of Flow Direction
Authors: Wang Chong , Baker Brendon M. , Chen Christopher S. , Schwartz Martin Alexander
Published: June 2013

Objective—

Atherosclerosis-prone regions of arteries are characterized by complex flow patterns where the magnitude of shear stress is low and direction rapidly changes, termed disturbed flow. How endothelial cells sense flow direction and how it impacts inflammatory effects of disturbed flow are unknown. We therefore aimed to understand how endothelial cells respond to changes in flow direction.

Approach and Results—

Using a recently developed flow system capable of changing flow direction to any angle, we show that responses of aligned endothelial cells are determined by flow direction relative to their morphological and cytoskeletal axis. Activation of the atheroprotective endothelial nitric oxide synthase pathway is maximal at 180° and undetectable at 90°, whereas activation of proinflammatory nuclear factor-κB is maximal at 90° and undetectable at 180°. Similar effects were observed in randomly oriented cells in naive monolayers subjected to onset of shear. Cells aligned on micropatterned substrates subjected to oscillatory flow were also examined. In this system, parallel flow preferentially activated endothelial nitric oxide synthase and production of nitric oxide, whereas perpendicular flow preferentially activated reactive oxygen production and nuclear factor-κB.

Conclusions—

These data show that the angle between flow and the cell axis defined by their shape and cytoskeleton determines endothelial cell responses. The data also strongly suggest that the inability of cells to align in low and oscillatory flow is a key determinant of the resultant inflammatory activation.
Clinical Profile and Underdiagnosis of Pulmonary Hypertension in US Veteran Patients
Authors: Maron Bradley A. , Choudhary Gaurav , Khan Umar A. , Jankowich Matthew D. , McChesney Hope , Ferrazzani Sarah J. , Gaddam Sainath , Sharma Satish , Opotowsky Alexander R. , Bhatt Deepak L. , Rocco Thomas P. , Aragam Jayashri R.
Published: June 2013

Background—

Pulmonary hypertension (PH) is a key contributor to cardiovascular morbidity and early mortality; however, reports are lacking on the epidemiology of PH in at-risk patient populations.

Methods and Results—

The echocardiography registries from 2 major Veterans Affairs hospitals were accessed to identify patients with at least moderate PH, defined here as a pulmonary artery systolic pressure ≥60 mm Hg detected echocardiographically. From a total of 10 471 individual patient transthoracic echocardiograms, we identified moderate or severe PH in 340 patients (332 men; mean, 77 years; mean pulmonary artery systolic pressure, 69.4±10.5 mm Hg), of which PH was listed as a diagnosis in the medical record for only 59 (17.3%). At a mean of 832 days (0–4817 days) following echocardiography diagnosing PH, 150 (44.1%) patients were deceased. PH was present without substantial left heart remodeling: the mean left ventricular ejection fraction was 0.50±0.16, left ventricular end-diastolic dimension was 5.0±0.9 cm, and left atrial dimension was 4.4±0.7 cm. Cardiac catheterization (n=122, 36%) demonstrated a mean pulmonary artery pressure of 40.5±11.4 mm Hg, pulmonary capillary wedge pressure of 22.6±8.9 mm Hg, and pulmonary vascular resistance of 4.6±2.9 Wood units. Diagnostic strategies for PH were variable and often incomplete; for example, only 16% of appropriate patients were assessed with a nuclear ventilation/perfusion scan for thromboembolic causes of PH.

Conclusions—

In an at-risk patient population, PH is underdiagnosed and associated with substantial mortality. Enhanced awareness is necessary among practitioners regarding contemporary PH diagnostic strategies.
Validity and Reliability of a Novel Slow Cuff-Deflation System for Noninvasive Blood Pressure Monitoring in Patients With Continuous-Flow Left Ventricular Assist Device
Authors: Lanier Gregg M. , Orlanes Khristine , Hayashi Yacki , Murphy Jennifer , Flannery Margaret , Te-Frey Rosie , Uriel Nir , Yuzefpolskaya Melana , Mancini Donna M. , Naka Yoshifumi , Takayama Hiroo , Jorde Ulrich P. , Demmer Ryan T. , Colombo Paolo C.
Published: June 2013

Background—

Doppler ultrasound is the clinical gold standard for noninvasive blood pressure (BP) measurement among continuous-flow left ventricular assist device patients. The relationship of Doppler BP to systolic BP (SBP) and mean arterial pressure (MAP) is uncertain and Doppler measurements require a clinic visit. We studied the relationship between Doppler BP and both arterial-line (A-line) SBP and MAP. Validity and reliability of the Terumo Elemano BP Monitor, a novel slow cuff-deflation device that could potentially be used by patients at home, were assessed.

Methods and Results—

Doppler and Terumo BP measurements were made in triplicate among 60 axial continuous-flow left ventricular assist device (HeartMate II) patients (30 inpatients and 30 outpatients) at 2 separate exams (360 possible measurements). A-line measures were also obtained among inpatients. Mean absolute differences (MADs) and correlations were used to determine within-device reliability (comparison of second and third BP measures) and between-device validity. Bland–Altman plots assessed BP agreement between A-line, Doppler BP, and Terumo Elemano. Success rates for Doppler and Terumo Elemano were 100% and 91%. Terumo Elemano MAD for repeat SBP and MAP were 4.6±0.6 and 4.2±0.6 mm Hg; repeat Doppler BP MAD was 2.9±0.2 mm Hg. Mean Doppler BP was lower than A-line SBP by 4.1 (MAD=6.4±1.4) mm Hg and higher than MAP by 9.5 (MAD=11.0±1.2) mm Hg; Terumo Elemano underestimated A-line SBP by 0.3 (MAD=5.6±0.9) mm Hg and MAP by 1.7 (MAD=6.0±1.0) mm Hg.

Conclusions—

Doppler BP more closely approximates SBP than MAP. Terumo Elemano was successful, reliable, and valid when compared with A-line and Doppler.
Longitudinal Changes in Left Ventricular Stiffness
Authors: Borlaug Barry A. , Redfield Margaret M. , Melenovsky Vojtech , Kane Garvan C. , Karon Barry L. , Jacobsen Steven J. , Rodeheffer Richard J.
Published: June 2013

Background—

Cross-sectional studies suggest that left ventricular (LV) and arterial elastance (stiffness) increase with age, but data examining longitudinal changes within human subjects are lacking. In addition, it remains unknown whether age-related LV stiffening is merely a reaction to arterial stiffening or caused by other processes.

Methods and Results—

Comprehensive echo-Doppler cardiography was performed in 1402 subjects participating in a randomly selected community-based study at 2 examinations separated by 4 years. From this population, 788 subjects had adequate paired data to determine LV end-systolic elastance (Ees), end-diastolic elastance (Eed), and effective arterial elastance. Throughout 4 years, blood pressure, arterial elastance, and LV mass decreased, coupled with significantly greater use of antihypertensive medications. However, despite reductions in arterial load, Ees increased by 14% (2.10±0.67–2.26±0.70 mm Hg/mL;
P
<0.0001) and Eed increased by 8% (0.13±0.03–0.14±0.04 mm Hg/mL;
P
<0.0001). Increases in Eed were greater in women than men, whereas Ees changes were similar. Age-related increases in Ees and Eed were correlated with changes in body weight, but were similar in subjects with or without cardiovascular disease. Changes in Ees were correlated with Eed (
r
=0.5;
P
<0.0001), but not with other measures of contractility, indicating that the increase in Ees was reflective of passive stiffening rather than enhanced systolic function.

Conclusions—

Despite reductions in arterial load with medical therapy, LV systolic and diastolic stiffness increase over time in humans, particularly in women. In addition to blood pressure control, therapies targeting load-independent ventricular stiffening may be effective to treat and prevent age-associated cardiovascular diseases, such as heart failure.
Identification of Nodal Tissue in the Living Heart Using Rapid Scanning Fiber-Optics Confocal Microscopy and Extracellular Fluorophores
Authors: Huang Chao , Kaza Aditya K. , Hitchcock Robert W. , Sachse Frank B.
Published: June 2013

Background—

Risks associated with pediatric reconstructive heart surgery include injury of the sinoatrial node (SAN) and atrioventricular node (AVN), requiring cardiac rhythm management using implantable pacemakers. These injuries are the result of difficulties in identifying nodal tissues intraoperatively. Here we describe an approach based on confocal microscopy and extracellular fluorophores to quantify tissue microstructure and identify nodal tissue.

Methods and Results—

Using conventional 3-dimensional confocal microscopy we investigated the microstructural arrangement of SAN, AVN, and atrial working myocardium (AWM) in fixed rat heart. AWM exhibited a regular striated arrangement of the extracellular space. In contrast, SAN and AVN had an irregular, reticulated arrangement. AWM, SAN, and AVN tissues were beneath a thin surface layer of tissue that did not obstruct confocal microscopic imaging. Subsequently, we imaged tissues in living rat hearts with real-time fiber-optics confocal microscopy. Fiber-optics confocal microscopy images resembled images acquired with conventional confocal microscopy. We investigated spatial regularity of tissue microstructure from Fourier analysis and second-order image moments. Fourier analysis of fiber-optics confocal microscopy images showed that the spatial regularity of AWM was greater than that of nodal tissues (37.5±5.0% versus 24.3±3.9% for SAN and 23.8±3.7% for AVN;
P
<0.05). Similar differences of spatial regularities were revealed from second-order image moments (50.0±7.3% for AWM versus 29.3±6.7% for SAN and 27.3±5.5% for AVN;
P
<0.05).

Conclusions—

The study demonstrates feasibility of identifying nodal tissue in living heart using extracellular fluorophores and fiber-optics confocal microscopy. Application of the approach in pediatric reconstructive heart surgery may reduce risks of injuring nodal tissues.
Outcome Prediction by Quantitative Right Ventricular Function Assessment in 575 Subjects Evaluated for Pulmonary Hypertension
Authors: Fine Nowell M. , Chen Libo , Bastiansen Paul M. , Frantz Robert P. , Pellikka Patricia A. , Oh Jae K. , Kane Garvan C.
Published: June 2013

Background—

Although right ventricular (RV) dysfunction is a major determinant of outcome in patients with pulmonary hypertension (PH), the optimal measure of RV function is poorly defined. We hypothesized that RV strain measured by speckle-tracking echocardiography predicts outcome in PH over a broad range of pulmonary pressures.

Methods and Results—

Prospective peak RV longitudinal systolic strain measurement was performed on 575 patients (mean age, 56±18 years; 63% women) referred for echocardiography for known or suspected PH. Survival status was assessed over a median of 16.5 (interquartile range, 7.6–20.0) months. There were 406 patients with PH (71%) (74% group 1, 14% group 3, and 12% group 4) and 169 patients without evidence of PH (29%). Among patients with PH, 46% were World Health Organization functional class III–IV. The mean RV strain was −21.2±6.7% for all patients. RV strain declined with worse functional class, shorter 6-minute walk distances, higher N-terminal pro-B-type natriuretic peptide levels, and the presence of right heart failure. RV strain predicted outcome across pulmonary pressures and groups of PH. Eighteen-month survival was 92%, 88%, 85%, and 71% according to RV strain quartile (
P
<0.001), with a 1.46 higher risk of death (95% confidence interval, 1.05–2.12) per 6.7% decline in RV strain. RV strain predicted survival when adjusted for pulmonary pressure, pulmonary vascular resistance, and right atrial pressure and provided incremental prognostic value over conventional clinical and echocardiographic variables.

Conclusions—

Quantitative assessment of RV free-wall systolic strain is feasible and is a powerful predictor of the clinical outcome of patients with known or suspected PH.