Athletic equipment microbiota are shaped by interactions with human skin

© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Microbiome 3 (2015): 25, doi:10.1186/s40168-015-0088-3.Americans spend the vast majority of their lives in built environments. Even traditionally outdoor pursuits, such as exercising, are often now performed indoors. Bacteria that colonize these indoor ecosystems are primarily derived from the human microbiome. The modes of human interaction with indoor surfaces and the physical conditions associated with each surface type determine the steady-state ecology of the microbial community. Bacterial assemblages associated with different surfaces in three athletic facilities, including floors, mats, benches, free weights, and elliptical handles, were sampled every other hour (8 am to 6 pm) for 2 days. Surface and equipment type had a stronger influence on bacterial community composition than the facility in which they were housed. Surfaces that were primarily in contact with human skin exhibited highly dynamic bacterial community composition and non-random co-occurrence patterns, suggesting that different host microbiomes—shaped by selective forces—were being deposited on these surfaces through time. However, bacterial assemblages found on the floors and mats changed less over time, and species co-occurrence patterns appeared random, suggesting more neutral community assembly. These longitudinal patterns highlight the dramatic turnover of microbial communities on surfaces in regular contact with human skin. By uncovering these longitudinal patterns, this study promotes a better understanding of microbe-human interactions within the built environment.MW was supported by a Weinberg College of Arts and Sciences Summer Grant from Northwestern University. This work was supported in part by the U.S. Dept. of Energy under Contract DE-AC02-06CH11357. This work was also supported by the Alfred P Sloan Foundation’s Microbiology of the Built Environment research program. SMG was supported by an EPA STAR Graduate Fellowship and the National Institutes of Health Training Grant 5 T-32 EB-009412

Left atrial reservoir strain by speckle tracking echocardiography : association with exercise capacity in chronic kidney disease

BACKGROUND: Left atrial (LA) function plays a pivotal role in modulating left ventricular performance. The aim of our study was to evaluate the relationship between resting LA function by strain analysis and exercise capacity in patients with chronic kidney disease (CKD) and evaluate its utility compared with exercise E/e’. METHODS AND RESULTS: Consecutive patients with stage 3 and 4 CKD without prior cardiac history were prospectively recruited from outpatient nephrology clinics and underwent clinical evaluation and resting and exercise stress echocardiography. Resting echocardiographic parameters including E/e’ and phasic LA strain (LA reservoir [LASr], conduit, and contractile strain) were measured and compared with exercise E/e’. A total of 218 (63.9±11.7 years, 64% men) patients with CKD were recruited. Independent clinical parameters associated with exercise capacity were age, estimated glomerular filtration rate, body mass index, and sex (P<0.01 for all), while independent resting echocardiographic parameters included E/e’, LASr, and LA contractile strain (P<0.01 for all). Among resting echocardiographic parameters, LASr demonstrated the strongest positive correlation to metabolic equivalents achieved (r=0.70; P<0.01). Receiver operating characteristic curves demonstrated that LASr (area under the curve, 0.83) had similar diagnostic performance as exercise E/e’ (area under the curve, 0.79; P=0.20 on DeLong test). A model combining LASr and clinical metrics showed robust association with metabolic equivalents achieved in patients with CKD. CONCLUSIONS: LASr, a marker of decreased LA compliance is an independent correlate of exercise capacity in patients with stage 3 and 4 CKD, with similar diagnostic value to exercise E/e’. Thus, LASr may serve as a resting biomarker of functional capacity in this population

Hypertension accelerates the 'normal' aging process with a premature increase in left atrial volume

Hypertension (HT) is associated with left ventricular (LV) diastolic dysfunction and consequent left atrial (LA) dilatation. We investigated changes in LA size and phasic function by decade in patients with HT. Patients with mild or moderate HT (n = 122) were compared with a case controlled normal cohort (blood pressure <140/90 mm Hg). Biplane LA maximum, minimum, and pre 'a' wave volumes were measured; LA filling, passive emptying, and active emptying volumes and fractions were calculated. Transmitral inflow and pulsed wave mitral annular tissue Doppler velocity were measured as expressions of LV diastolic function. The HT group had larger LA maximum volumes compared with normal controls for all decades until the 8th decade. Subjects with HT in decade 4 had LA maximum volume similar to that of normal controls from decade 8 (27.8 ± 4.3 mL/m2 vs 25.6 ± 6.1 mL/m2 respectively, P =.22). Active emptying volume and fraction were higher in the HT group across all decades, while there was no difference between the HT and normal groups for passive emptying volume. LV mass and E/E? ratio were significantly higher across all decades in the HT group. HT alters atrial dynamics significantly, with resultant increased LA volume and active emptying volume consequent to altered LV diastolic function. HT 'accelerates' the normal aging process with patients as early as decade 4 having similar LA size to that of normal controls in decade 8. This premature increase in LA volume may result in the future development of atrial fibrillation in HT patients

Comparison of left atrial phasic function in hypertrophic cardiomyopathy versus systemic hypertension using strain rate imaging

The aim of this study was to determine if left atrial (LA) phasic function evaluated by Doppler tissue imagingderived strain and strain rate would be differentially decreased in patients with hypertrophic cardiomyopathy (HC) compared to patients with hypertension and to normal controls. Thirty-seven patients with HC were compared to 44 patients with systemic hypertension (SH) and 65 normal controls using transthoracic echocardiography. Maximal and minimal LA volume and LA volume just before active atrial contraction (pre-P LA volume) were measured, and phasic LA volumes were calculated. Global and segmental systolic strain rate, early diastolic strain rate, and late diastolic strain rate (A-Sr) and strain were measured from Doppler tissue imaging. Left ventricular mass was increased in the HC and SH groups compared to normal controls, but diastolic dysfunction was greater in the HC group. LA volumes were increased in patients with HC compared to those with SH and to normal controls, with corresponding reductions in A-Sr and atrial strain in the HC group. In contrast, only early diastolic strain rate was decreased in the SH group compared to controls. A-Sr remained reduced in patients with HC compared to the SH group, even after adjusting for left ventricular mass. When left ventricular mass, parameters of diastolic function (peak E and E′ velocity), and the effect of patient group (SH vs HC) were examined in a stepwise regression model, patient group (SH vs HC) was the only independent determinant of A-Sr. In conclusion, HC results in LA enlargement with reduced LA phasic function that is reflected in reductions in A-Sr and atrial strain. Atrial enlargement is a likely consequence of the greater diastolic dysfunction in the HC group

Cardiac vignette : isolated pulmonary regurgitation

Isolated pulmonary regurgitation (PR) is a rare occurrence with only a handful of documented cases worldwide. Though usually well tolerated in childhood, chronic PR can eventually lead to RV dysfunction and ventricular arrhythmias. In this cardiac vignette, we describe a case of isolated PR in a young female presenting with syncope and explore the natural history, different investigative modalities as well as issues in clinical management of this rare condition

Exercise E/e' is a determinant of exercise capacity and adverse cardiovascular outcomes in chronic kidney disease

Objectives: This study sought to assess the relationship between E/e′ and exercise capacity in patients with chronic kidney disease (CKD) and evaluate its prognostic role. Background: Patients with CKD have diastolic dysfunction, reduced physical fitness, and elevated risk of cardiovascular disease. Methods: Patients with stage 3 and 4 CKD without previous cardiac disease underwent resting and exercise stress echocardiograms with assessment of exercise E/e′. Patients were compared to age-, sex-, and risk factor–matched control individuals and were followed annually for 5 years for cardiovascular death and major adverse cardiovascular event(s) (MACE). Exercise capacity was assessed as metabolic equivalents (METs), with reduced exercise capacity defined as METs of ≤7. Raised exercise E/e′ was defined as >13. Results: A total of 156 patients with CKD (age 62.8 ± 10.6 years; male: 62%) were compared to 156 matched control individuals. Patients with CKD were more likely to be anemic (p 13 was an independent predictor of cardiovascular death and MACE on unadjusted and adjusted hazard models. Conclusion: E/e′ is a strong predictor of exercise capacity and METs achieved by patients with CKD. Exercise capacity was reduced in patients with CKD, presumably consequent to diastolic dysfunction. Elevated exercise E/e′ in patients with CKD is an independent predictor of cardiovascular death and MACE

Changes in left atrial volume in diabetes mellitus : more than diastolic dysfunction?

To evaluate left atrial (LA) volume and function as assessed by strain and strain rate derived from 2D speckle tracking and their association with diastolic dysfunction (DD) in patients with diabetes mellitus (DM). Seventy three patients with DM were compared with age- and gender-matched normal controls; 30 patients with DM alone were compared to those with hypertension (HT) alone. The maximum LA volume, traditional measures of atrial function, 2D strain and strain rate were analysed. The LA indexed volume (LAVI) was larger in DM group than that in normal controls (38.2 9.9 vs. 20.5 4.8 ml/m(2), P 0.0001), as well as in DM alone compared with hypertensive patients (33.9 10 vs. 25.7 8 ml/m(2), P 0.0001). Global strain was significantly reduced in the DM group compared with that in normal controls (22.5 8.67 vs. 30.6 8.27; P 0.0001) but was similar with HT. There was a weak correlation between LAVI and global strain with increasing grades of DD (r 0.439, P 0.0001 and r 0.316, P 0.0001, respectively) in the diabetic group. However, there was no significant difference in LAVI between these groups. A logistic regression analysis for predictors of LAVI demonstrated that only diabetes was a determinant of LAVI. Patients with diabetes showed a significant reduction in global strain compared with normal controls but no difference with increasing grades of diastolic function. LA enlargement in DM is independent of associated HT and diastolic function. LA enlargement is associated with LA dysfunction as evaluated by 2D strain. It is likely that a combination of DD and a diabetic atrial myopathy contribute to LA enlargement in patients with DM

Determinants of LA reservoir strain : independent effects of LA volume and LV global longitudinal strain

Background: Left atrial (LA) deformation during the reservoir phase (LASr) has demonstrated strong prognostic value in different clinical settings. Although determinants of left atrial reservoir strain including left atrial relaxation, left atrial compliance, and left ventricular longitudinal systolic function are fairly well defined, there is incomplete information regarding the effect of left atrial volume on this relationship which is the focus of our study. Method: Consecutive patients without prior cardiac disease referred for transthoracic echocardiography were prospectively recruited. All participants underwent clinical assessment, transthoracic echocardiography (TTE), and screening exercise stress test. Only patients with normal left ventricular ejection fraction (LVEF) without left ventricular hypertrophy (LVH) or myocardial ischemia on stress testing were included. Results: A total of 260 patients (57% male, mean age 59 ± 14 years) were included. 70% had hypertension, 33% had diabetes mellitus, and 31% had both HTN and DM. On multivariate analysis, age, e’, LAVI, and LV GLS (P < .01 for all) showed an independent association with LASr. Of interest, at lower tertiles of LAVI, a linear decrease in LASr was observed parallel to worsening LV GLS, whilst at higher tertiles of LAVI, the reduction in LASr was non-linear implying that LA enlargement, consequent to LA remodeling, had an incremental effect on LASr. Conclusion: Age, e’, LV GLS, and LAVI were independently associated with LASr. LA remodeling reflected by larger LAVI had an incremental negative association with LASr independent of LV GLS