Six-month exercise training program to treat post-thrombotic syndrome: a randomized controlled two-centre trial

Background

Exercise training may have the potential to improve post-thrombotic syndrome, a frequent, chronic complication of deep venous thrombosis. We conducted a randomized controlled two-centre pilot trial to assess the feasibility of a multicentre-based evaluation of a six-month exercise training program to treat post-thrombotic syndrome and to obtain preliminary data on the effectiveness of such a program.

Methods

Patients were randomized to receive exercise training (a six-month trainer-supervised program) or control treatment (an education session with monthly phone follow-ups). Levels of eligibility, consent, adherence and retention were used as indicators of study feasibility. Primary outcomes were change from baseline to six months in venous disease-specific quality of life (as measured using the Venous Insufficiency Epidemiological and Economic Study Quality of Life [VEINES-QOL] questionnaire) and severity of post-thrombotic syndrome (as measured by scores on the Villalta scale) in the exercise training group versus the control group, assessed by t tests. Secondary outcomes were change in generic quality of life (as measured using the Short-Form Health Survey-36 [SF-36] questionnaire), category of severity of post-thrombotic syndrome, leg strength, leg flexibility and time on treadmill.

Results

Of 95 patients with post-thrombotic syndrome, 69 were eligible, 43 consented and were randomized, and 39 completed the study. Exercise training was associated with improvement in VEINES-QOL scores (exercise training mean change 6.0, standard deviation [SD] 5.1 v. control mean change 1.4, SD 7.2; difference 4.6, 95% CI 0.54 to 8.7; p = 0.027) and improvement in scores on the Villalta scale (exercise training mean change −3.6, SD 3.7 v. control mean change −1.6, SD 4.3; difference −2.0, 95% CI −4.6 to 0.6; p = 0.14). Most secondary outcomes also showed greater improvement in the exercise training group.

Interpretation

Exercise training may improve post-thrombotic syndrome. It would be feasible to definitively evaluate exercise training as a treatment for post-thrombotic syndrome in a large multicentre trial.Chronic post-thrombotic syndrome develops in up to one-half of patients with deep venous thrombosis and is associated with varying combinations of leg pain, heaviness, swelling, edema, hyperpigmentation and varicose collateral veins. In severe instances, lipodermatosclerosis and venous ulcers occur.¹ Patients with post-thrombotic syndrome have substantially impaired quality of life.^2,3 Given that effective treatments are lacking, new approaches to managing post-thrombotic syndrome are needed.⁴Exercise training is an effective treatment for arterial claudication^5,6 and may also improve post-thrombotic syndrome.⁷ Potential mechanisms include improved endurance resulting from increased aerobic capacity, reduced muscular effort from improved strength, reduced swelling and discomfort via improved function of the calf muscle pump and improved muscu-loskeletal function via increased flexibility of ankle and knee joints.^8,9We performed a pilot trial to obtain data on the effectiveness of exercise training to treat post-thrombotic syndrome and to assess the feasibility of performing a multicentre study to address this question.     

Sudden cardiac death thirty years ago and at present. The role of autonomic disturbances in acute myocardial infarction revisited

The most common cause of sudden cardiac death is ventricular fibrillation (VF). In addition to the status, size and location of the ventricular focus, a major pathogenic mechanism triggering VF is autonomic dysbalance (disturbance). This term refers to a wide range of reflex changes in the ratio of sympathetic to vagal ventricular activation over time, occurring immediately after coronary artery occlusion at the onset of acute myocardial infarction (AMI). Another trigger of VF is autonomic disturbance due to emotional stress. Experimental and clinical research into autonomic disturbances associated with coronary artery occlusion and emotional stress was given considerable attention as early as some 30 years ago when researchers were already searching for ways of inhibiting autonomic disturbances using predominant sympathetic and vagal activation by beta-blockers (BB) and atropine, respectively. The aim of our paper is to compare results obtained 30 years ago with current status of experimental and clinical research into SCD prevention. Another aim is to identify questions that have remained unanswered to date; answers to these outstanding questions could help further reduce the risk of SCD.     

Extracting Transition Rates in Particle Tracking Using Analytical Diffusion Distribution Analysis

Single-particle tracking is an important technique in the life sciences to understand the kinetics of biomolecules. The analysis of apparent diffusion coefficients in vivo, for example, enables researchers to determine whether biomolecules are moving alone, as part of a larger complex, or are bound to large cellular components such as the membrane or chromosomal DNA. A remaining challenge has been to retrieve quantitative kinetic models, especially for molecules that rapidly switch between different diffusional states. Here, we present analytical diffusion distribution analysis (anaDDA), a framework that allows for extracting transition rates from distributions of apparent diffusion coefficients calculated from short trajectories that feature less than 10 localizations per track. Under the assumption that the system is Markovian and diffusion is purely Brownian, we show that theoretically predicted distributions accurately match simulated distributions and that anaDDA outperforms existing methods to retrieve kinetics, especially in the fast regime of 0.1–10 transitions per imaging frame. AnaDDA does account for the effects of confinement and tracking window boundaries. Furthermore, we added the option to perform global fitting of data acquired at different frame times to allow complex models with multiple states to be fitted confidently. Previously, we have started to develop anaDDA to investigate the target search of CRISPR-Cas complexes. In this work, we have optimized the algorithms and reanalyzed experimental data of DNA polymerase I diffusing in live Escherichia coli. We found that long-lived DNA interaction by DNA polymerase are more abundant upon DNA damage, suggesting roles in DNA repair. We further revealed and quantified fast DNA probing interactions that last shorter than 10 ms. AnaDDA pushes the boundaries of the timescale of interactions that can be probed with single-particle tracking and is a mathematically rigorous framework that can be further expanded to extract detailed information about the behavior of biomolecules in living cells.     

New and Old World phylogeography of pumpkinseed Lepomis gibbosus (Linnaeus, 1758): the North American origin of introduced populations in Europe

Hydrobiologia - To determine the origin of introduced European populations of pumpkinseed Lepomis gibbosus (Linnaeus, 1758)—a freshwater sunfish, native to eastern North America that has...     

CRISPR-based DNA and RNA detection with liquid-liquid phase separation

The ability to detect specific nucleic acid sequences allows for a wide range of applications such as the identification of pathogens, clinical diagnostics, and genotyping. CRISPR-Cas proteins Cas12a and Cas13a are RNA-guided endonucleases that bind and cleave specific DNA and RNA sequences, respectively. After recognition of a target sequence, both enzymes activate indiscriminate nucleic acid cleavage, which has been exploited for sequence-specific molecular diagnostics of nucleic acids. Here, we present a label-free detection approach that uses a readout based on solution turbidity caused by liquid-liquid phase separation (LLPS). Our approach relies on the fact that the LLPS of oppositely charged polymers requires polymers to be longer than a critical length. This length dependence is predicted by the Voorn-Overbeek model, which we describe in detail and validate experimentally in mixtures of polynucleotides and polycations. We show that the turbidity resulting from LLPS can be used to detect the presence of specific nucleic acid sequences by employing the programmable CRISPR-nucleases Cas12a and Cas13a. Because LLPS of polynucleotides and polycations causes solutions to become turbid, the detection of specific nucleic acid sequences can be observed with the naked eye. We furthermore demonstrate that there is an optimal polynucleotide concentration for detection. Finally, we provide a theoretical prediction that hints towards possible improvements of an LLPS-based detection assay. The deployment of LLPS complements CRISPR-based molecular diagnostic applications and facilitates easy and low-cost nucleotide sequence detection.     

Evaluating the Mechanisms of Landscape Change on White-Tailed Deer Populations

Understanding how landscape change influences the distribution and densities of species, and the consequences of these changes, is a central question in modern ecology. The distribution of white-tailed deer (Odocoileus virginianus) is expanding across North America, and in some areas, this pattern has led to an increase in predators and consequently higher predation rates on woodland caribou (Rangifer tarandus caribou)—an alternate prey species that is declining across western Canada. Understanding the factors influencing deer distribution has therefore become important for effective conservation of caribou in Canada. Changing climate and anthropogenic landscape alteration are hypothesized to facilitate white-tailed deer expansion. Yet, climate and habitat alteration are spatiotemporally correlated, making these factors difficult to isolate. Our study evaluates the relative effects of snow conditions and human-modified habitat (habitat alteration) across space on white-tailed deer presence and relative density. We modeled deer response to snow depth and anthropogenic habitat alteration across a large latitudinal gradient (49° to 60°) in Alberta, Canada, using motion-sensitive camera data collected in winter and spring from 2015 to 2019. Deer distribution in winter and spring were best explained by models including both snow depth and habitat alteration. Sites with shallower snow had higher deer presence regardless of latitude. Increased habitat alteration increased deer presence in the northern portion of the study area only. Winter deer density was best explained by snow depth only, whereas spring density was best explained by both habitat alteration and the previous winter's snow depth. Our results suggest that limiting future habitat alteration or restoring habitat can alter deer distribution, thereby potentially slowing or reversing expansion, but that climate plays a significant role beyond what managers can influence. © 2020 The Wildlife Society.     

Secondary (iso)BAs cooperate with endogenous ligands to activate FXR under physiological and pathological conditions

IsoBAs, stereoisomers of primary and secondary BAs, are found in feces and plasma of human individuals. BA signaling via the nuclear receptor FXR is crucial for regulation of hepatic and intestinal physiology/pathophysiology. Aim: Investigate the ability of BA-stereoisomers to bind and modulate FXR under physiological/pathological conditions. Methods: Expression-profiling, luciferase-assays, fluorescence-based coactivator-association assays, administration of (iso)-BAs to WT and cholestatic mice. Results: Compared to CDCA/isoCDCA, administration of DCA/isoDCA, UDCA/isoUDCA only slightly increased mRNA expression of FXR target genes; the induction was more evident looking at pre-mRNAs. Notably, almost 50% of isoBAs were metabolized to 3-oxo-BAs within 4 h in cell-based assays, making it difficult to study their actions. FRET-based real-time monitoring of FXR activity revealed that isoCDCA>CDCA stimulated FXR, and isoDCA and isoUDCA allowed fully activated FXR to be re-stimulated by a second dose of GW4064. In vivo co-administration of a single dose of isoBAs followed by GW4064 cooperatively activated FXR, as did feeding of UDCA in a background of endogenous FXR ligands. However, in animals with biliary obstruction and concomitant loss of intestinal BAs, UDCA was unable to increase intestinal Fgf15. In contrast, mice with an impaired enterohepatic circulation of BAs (Asbt?/?, Ostα?/?), administration of UDCA was still able to induce ileal Fgf15 and repress hepatic BA-synthesis, arguing that UDCA is only effective in the presence of endogenous FXR ligands. Conclusion: Secondary (iso)BAs cooperatively activate FXR in the presence of endogenous BAs, which is important to consider in diseases linked to disturbances in BA enterohepatic cycling.     

The novel plasminogen receptor, plasminogen receptor(KT) (Plg-R(KT)), regulates catecholamine release

Neurotransmitter release by catecholaminergic cells is negatively regulated by prohormone cleavage products formed from plasmin-mediated proteolysis. Here, we investigated the expression and subcellular localization of Plg-R(KT), a novel plasminogen receptor, and its role in catecholaminergic cell plasminogen activation and regulation of catecholamine release. Prominent staining with anti-Plg-R(KT) mAb was observed in adrenal medullary chromaffin cells in murine and human tissue. In Western blotting, Plg-R(KT) was highly expressed in bovine adrenomedullary chromaffin cells, human pheochromocytoma tissue, PC12 pheochromocytoma cells, and murine hippocampus. Expression of Plg-R(KT) fused in-frame to GFP resulted in targeting of the GFP signal to the cell membrane. Phase partitioning, co-immunoprecipitation with urokinase-type plasminogen activator receptor (uPAR), and FACS analysis with antibody directed against the C terminus of Plg-R(KT) were consistent with Plg-R(KT) being an integral plasma membrane protein on the surface of catecholaminergic cells. Cells stably overexpressing Plg-R(KT) exhibited substantial enhancement of plasminogen activation, and antibody blockade of non-transfected PC12 cells suppressed plasminogen activation. In functional secretion assays, nicotine-evoked [(3)H]norepinephrine release from cells overexpressing Plg-R(KT) was markedly decreased (by 51 ± 2%, p < 0.001) when compared with control transfected cells, and antibody blockade increased [(3)H]norepinephrine release from non-transfected PC12 cells. In summary, Plg-R(KT) is present on the surface of catecholaminergic cells and functions to stimulate plasminogen activation and modulate catecholamine release. Plg-R(KT) thus represents a new mechanism and novel control point for regulating the interface between plasminogen activation and neurosecretory cell function.