Acute Exercise Activates Pulmonary eNOS and Lowers Pulmonary Pressure in Rats with Pulmonary Arterial Hypertension

poster abstractNO-dependent arterial relaxation is impaired in pulmonary arterial hypertension (PAH). Exercise may be beneficial in PAH, just as it is for systemic vascular disease, via upregulation of endothelial nitric oxide synthase (eNOS) expression and activity. However, exercise-induced cardiac stress in PAH could also promote detrimental RV inflammation. We investigated pulmonary pressure and eNOS, as well inflammatory indicators in the RV, following a single 45 min run bout at moderate intensity in a rat model of PAH. Male Sprague-Dawley rats received either monocrotaline to induce PAH, or saline, for healthy controls. A subset of PAH and healthy controls performed 4 wks of progressive TM familiarization (15-30min, 8-20 m/min) in preparation for their final 45 min run @ 75% of VO2max. Immediately following the run, RV systolic pressure was measured and RV and lung tissues were harvested and cryofixed. eNOS and phosphorylated (at Ser1177) eNOS (p-eNOS) was measured via immunoblotting in lung homogenates and expressed normalized to vinculin. Immunofluorescence for inflammatory markers CD45/68 in cryofixed RV sections evaluated the acute inflammatory response to exercise. MCT reduced VO2max and caused RV hypertrophy (expressed as RV/LV+septum) as consistent with this model. RVSP (normalized by systemic BP) was lower in PAH-Ex vs. unexercised PAH with no difference between exercised and unexercised controls. Greater p-eNOS was measured in PAH-Ex lung compared to unexercised PAH, with no difference between exercised and unexercised controls. PAH-Ex also tended to have greater pulmonary eNOS than their unexercised counterparts. No greater exercise-induced CD45/68 infiltration was observed in RV of PAH compared to that of controls. In rats with moderate MCT-induced PAH, a single exercise bout does not increase acute RV inflammation but lowers pulmonary pressure, possibly mediated in part via pulmonary eNOS activation

Microvascular inflammatory responses to ceramide and cigarette smoke in the intact rat assessed with intravital two-photon microscopy

poster abstractsmoke, characterized by alterations of the alveolar barrier function. We investigated this hypothesis by utilizing a novel application of intravital two-photon excitation microscopy (TPM) of the lung in a living, breathing animal. Methods: We first developed a technique of TPM to permit imaging of the lung maintained within the thoracic cavity of an intact rat. To accomplish this, we optimized the lung-microscope interface with an imaging window uniquely designed to minimize cardiac and respiratory motion during TPM acquisitions. To investigate alveolar barrier disruption in real time, we utilized intravenous (i.v.) fluorescent probes to examine changes in alveolar leukocyte trafficking and microvascular barrier function in response to i.v. ceramide (C16:0 PEG, 10 mg/kg), and to cigarette smoke extract (CSE) delivered i.v. (1ml/kg) or intratracheally via a nebulizer (2mL/kg). Results: We performed intravital TPM monitoring of the lung microcirculation of a living rat with maintained physiological cardio-pulmonary parameters for up to 3h. Time-lapse and 3-D reconstruction images revealed heterogeneous extravasation of FITC-labeled serum albumin from the alveolar microcirculation into the alveolar airspaces in response to ceramide, in a dose-dependent manner. Further, we noted that in response to both ceramide and to CSE, leukocytes accumulated in the lung parenchyma and demonstrated reduced mobility through the microcirculation, suggesting increased adhesion to the endothelium. Intratracheal administration of CSE caused increased extravasation of leukocytes into alveolar spaces within 10 minutes. Conclusions: We developed approaches that permit the application of intravital TPM to lung with no motion artifacts from the breathing and cardiac cycles. This approach permits visualization of the lung subpleural parenchyma with a high resolution. Both gross and subtle inflammatory changes that reflect alveolar epithelial and/or endothelial barrier dysfunction can be assessed with this methodology

A perpetual switching system in pulmonary capillaries

Of the 300 billion capillaries in the human lung, a small fraction meet normal oxygen requirements at rest, with the remainder forming a large reserve. The maximum oxygen demands of the acute stress response require that the reserve capillaries are rapidly recruited. To remain primed for emergencies, the normal cardiac output must be parceled throughout the capillary bed to maintain low opening pressures. The flow-distributing system requires complex switching. Because the pulmonary microcirculation contains contractile machinery, one hypothesis posits an active switching system. The opposing hypothesis is based on passive switching that requires no regulation. Both hypotheses were tested ex vivo in canine lung lobes. The lobes were perfused first with autologous blood, and capillary switching patterns were recorded by videomicroscopy. Next, the vasculature of the lobes was saline flushed, fixed by glutaraldehyde perfusion, flushed again, and then reperfused with the original, unfixed blood. Flow patterns through the same capillaries were recorded again. The 16-min-long videos were divided into 4-s increments. Each capillary segment was recorded as being perfused if at least one red blood cell crossed the entire segment. Otherwise it was recorded as unperfused. These binary measurements were made manually for each segment during every 4 s throughout the 16-min recordings of the fresh and fixed capillaries (>60,000 measurements). Unexpectedly, the switching patterns did not change after fixation. We conclude that the pulmonary capillaries can remain primed for emergencies without requiring regulation: no detectors, no feedback loops, and no effectors-a rare system in biology. NEW & NOTEWORTHY The fluctuating flow patterns of red blood cells within the pulmonary capillary networks have been assumed to be actively controlled within the pulmonary microcirculation. Here we show that the capillary flow switching patterns in the same network are the same whether the lungs are fresh or fixed. This unexpected observation can be successfully explained by a new model of pulmonary capillary flow based on chaos theory and fractal mathematics

Investigating Skeletal Muscle Metabolic Adaptations underlying Aerobic Fitness Gains following High Intensity Interval Training in a Rat Model of Pulmonary Arterial Hypertension

poster abstractRationale: In patients with pulmonary arterial hypertension (PAH) a shift from oxidative to a less efficient non-oxidative (glycolytic) metabolism in skeletal muscle is believed to contribute to the reduced exercise tolerance hallmark of the disease. As seen for other cardiopulmonary diseases, exercise training (ExT) may ameliorate this “glycolytic switch” in PAH and improve exercise capacity. Previous studies in this lab showed an improved metabolic profile of skeletal muscle in PAH rats following an ExT protocol of continuous running at moderate relative intensity, 60 minutes at 75% of maximal aerobic capacity (VO2 Max). This study tests the hypothesis in a PAH rat model that HIIT will also result in preserved aerobic capacity and attenuation of skeletal muscle glycolytic shift. Methods: Male Sprague-Dawley rats received either monocrotaline (MCT, 40 mg/kg) to induce mild PAH (n= 14), or saline, for healthy controls (n=9). After 2 wks, a 6 wkprogram of treadmill HIIT was initiated for a subset of PAH (n= 8) and healthy controls (n=6). The 30 min HIIT sessions alternated between 2 minutes at 85% VO2 max and 3 minutes at ~30% VO2 max. VO2 max was assessed at baseline, and in pre-training and post-training via analysis of expired gases. Preliminary results: MCT-induced decrement in VO2 max was attenuated by HIIT (p0.05). Western blotting of soleus homogenates for cytochromes I-V of the electron transport chain (OXPHOS), and for PGC1α, a potent stimulus for mitochondrial biogenesis, is being performed at present to further investigate potential training-induced adaptations in skeletal muscle metabolis

Exercise Training Improves Cardiac and Skeletal Muscle Metabolism in Rats with Pulmonary Arterial Hypertension

poster abstractIn patients with pulmonary arterial hypertension (PAH), a shift from oxidative to glycolytic metabolism promotes right ventricular (RV) and skeletal muscle dysfunction that contributes to reduced exercise tolerance. As seen for other cardiopulmonary diseases, exercise training (ExT) may ameliorate this glycolytic switch in PAH and improve exercise capacity. The purpose of this research is to investigate ExT in a rat model of PAH on markers of glycolytic and oxidative metabolism in RV and skeletal muscle. Male Sprague-Dawley rats received monocrotaline (MCT, 40 mg/kg, s.q.) to induce PAH (n= 13), or saline, for healthy controls (n=5). After 2 wks, with MCT-induced PAH established, 6 wks of treadmill (TM) ExT was initiated for a subset of PAH animals (PAH-ExT, n= 6) and healthy controls (CON-ExT, n=3). ExT runs progressed up to 60 min at mild relative intensity, 50% of maximal aerobic capacity (VO2max). VO2max was assessed at baseline, in pre-training and post-training TM testing via analysis of expired gases. Abundance of Glut-1, a marker of glycolytic metabolism, was evaluated in cryosections of RV and soleus with immunofluorescent (IF) staining and quantification. Data are presented as mean±SE. MCT-ExT rats maintained aerobic capacity over 6 wks better than sedentary counterparts (MCT-SED)(VO2max= -134±109 vs. -521±129 ml/kg/hr, p=0.04) and was not different than CON-ExT (-201±31 ml/kg/hr, p=0.82). A lower abundance of Glut-1 was observed in both RV and soleus myocytes of PAH-ExT rats (MPI= 10.9 ±0.9 for RV; 13.7±0.8 for soleus) compared to PAH-SED rats (15.7±2.4, p=0.05, for RV; 17.4±1.4, p=0.04, for soleus) and was similar to CON-ExT rats (13.0±2.2, p=0.33, for RV; 9.0±2.3, p=0.26, for soleus), indicative of a shift toward greater dependency on oxidative metabolism. Exercise training attenuates functional decline following MCT administration in rats. Preservation of aerobic capacity may be explained by promotion of more efficient RV and skeletal muscle mitochondrial substrate utilization

High Intensity Interval Training Benefits Right Heart Function in a Rat Model of Pulmonary Arterial Hypertension

poster abstractPulmonary Arterial Hypertension (PAH) is a disease of progressive remodeling in pulmonary arteries that elevates pulmonary pressures and eventually leads to right ventricular (RV) failure and death. The purpose of this study was to examine the benefit and detriment of high intensity interval training (HIIT) to the RV in a monocrotaline (MCT) PAH rat model. It is hypothesized that HIIT will improve indicators of RV function without increasing myocardial inflammation or apoptosis. Male Sprague Dawley rats were injected with either MCT (40 mg/kg, n=14)) to induce mild PAH or saline for healthy controls (CON, n=9). A subgroup of MCT (n= 8) and CON rats (n=6) performed a 6 week treadmill HIIT program 5x/week using short bouts of alternating high intensity (2 min, 85-90%VO2max) and low intensity (3 min, ~30%VO2max) running for 30 min/session. Histochemistry/immunohistochemistry was performed on cryofixed or formalin-fixed/paraffin-embedded RV sections to assess indicators of inflammation (CD45+ cells), apoptosis (TUNEL), fibrosis (trichrome) and was imaged using epifluorescence or brightfield microscopy. Image quantification was performed using ImageJ. For the HIIT rats, a reduction in MCTinduced RV hypertrophy was observed, as measured echocardiographically, and by the calculated ratio of RV mass relative to LV+Septum mass. RV function was better preserved for HIIT vs. sedentary MCT, as indicated by stroke volume and cardiac index (cardiac output normalized by body weight) in echocardiography. MCT-induced RV fibrosis as measured by trichrome staining was lower for HIIT, also indicating a healthier myocardium. HIIT did not prompt greater counts per field of CD45+ cells and TUNEL+ cells in HIIT vs. sedentary MCT RV myocardium. In conclusion, in the monocrotaline rat model of PAH, HIIT appears to be a beneficial exercise approach that improves RV function without exacerbating RV inflammation or apoptosis. Future work will examine effects in other PAH models and ultimately in patients with disease

High-intensity interval training, but not continuous training, reverses right ventricular hypertrophy and dysfunction in a rat model of pulmonary hypertension

Exercise is beneficial in pulmonary arterial hypertension (PAH), although studies to date indicate little effect on the elevated pulmonary pressures or maladaptive right ventricle (RV) hypertrophy associated with the disease. For chronic left ventricle failure, high-intensity interval training (HIIT) promotes greater endothelial stimulation and superior benefit than customary continuous exercise training (CExT); however, HIIT has not been tested for PAH. Therefore, here we investigated acute and chronic responses to HIIT vs. CExT in a rat model of monocrotaline (MCT)-induced mild PAH. Six weeks of treadmill training (5 times/wk) were performed, as either 30 min HIIT or 60 min low-intensity CExT. To characterize acute hemodynamic responses to the two approaches, novel recordings of simultaneous pulmonary and systemic pressures during running were obtained at pre- and 2, 4, 6, and 8 wk post-MCT using long-term implantable telemetry. MCT-induced decrement in maximal aerobic capacity was ameliorated by both HIIT and CExT, with less pronounced pulmonary vascular remodeling and no increase in RV inflammation or apoptosis observed. Most importantly, only HIIT lowered RV systolic pressure, RV hypertrophy, and total pulmonary resistance, and prompted higher cardiac index that was complemented by a RV increase in the positive inotrope apelin and reduced fibrosis. HIIT prompted a markedly pulsatile pulmonary pressure during running and was associated with greater lung endothelial nitric oxide synthase after 6 wk. We conclude that HIIT may be superior to CExT for improving hemodynamics and maladaptive RV hypertrophy in PAH. HIIT’s superior outcomes may be explained by more favorable pulmonary vascular endothelial adaptation to the pulsatile HIIT stimulus

MFA12 (MFA 2012)

Catalogue of a culminating student exhibition held at the Mildred Lane Kemper Art Museum May 4-Aug. 6, 2012. Contents include Introduction / Buzz Spector -- Think, make, show and tell / Patricia Olynyk -- Ifeoma Ugonnwa Anyaeji -- J.E. Baker / Elissa Yukiko Weichbrodt -- Natalie Baldeon / Emily Hanson -- As in a turning gear : E. Thurston Belmer / Rickey Laurentiis -- Lauren Cardenas / Nicholas Tamarkin -- Megan Sue Collins / Catherine Chiodo -- Adrian Cox -- Maya Durham / Dolly Laninga -- Erin Falker / Melissa Olson -- St. Louis dreamscape : Jieun Kim / Caitlin Tyler -- Howard Krohn -- Scape : Robert Long / Robert Whitehead -- Marie Bannerot McInerney / Elissa Yukiko Weichbrodt -- Ghost : Nikki McMahan / Rickey Laurentiis -- Michael T. Meier -- Katie Millitzer -- Reid G. Norris / Ross Rader -- Kathleen Perniciaro / Melissa Olson -- Emily Squires / Nicholas Tamarkin -- Jamie Presson Wells -- Whitney Lorene Wood / Reid G. Norris -- Andrew Woodard -- Kelly K. Wright -- Contributors -- About the Sam Fox School.https://openscholarship.wustl.edu/books/1003/thumbnail.jp

Urinary Diversion for Severe Urinary Adverse Events of Prostate Radiation: Results from a Multi-Institutional Study

PurposeWe evaluated the short and long-term surgical outcomes of urinary diversion done for urinary adverse events arising from prostate radiation therapy. We hypothesized that patient characteristics are associated with complications after urinary diversion.Materials and methodsWe performed a retrospective cohort study of 100 men who underwent urinary diversion (urinary conduit or continent catheterizable pouch) due to urinary adverse events after prostate radiotherapy from 2007 to 2016 from 9 academic centers in the United States. Outcome measurements included predictors of short and long-term complications, and readmission after urinary diversion of patients who had prostate cancer treated with radiotherapy. The data were summarized using descriptive statistics and univariate associations with complications were identified with logistic regression controlling for center.ResultsMean patient age was 71 years and median time from radiotherapy to urinary diversion was 8 years. Overall 81 (81%) patients had combined modality therapy (radical prostatectomy plus radiotherapy or various combinations of radiotherapy). Grade 3a or greater Clavien-Dindo complications occurred in 31 (35%) men, including 4 deaths (4.5%). Normal weight men had more short-term complications compared to overweight (OR 4.9, 95% CI 1.3-23.1, p=0.02) and obese men (OR 6.3, 95% CI 1.6-31.1, p=0.009). Hospital readmission within 6 weeks of surgery occurred for 35 (38%) men. Surgery was needed to treat long-term complications after urinary diversion in 19 (22%) patients with a median followup of 16.3 months.ConclusionsUrinary diversion after prostate radiotherapy has a considerable short and long-term surgical complication rate. Urinary diversion most often cannot be avoided in these patients but appreciation of the risks allows for informed shared decision making between surgeons and patients