The interplay between metabolic alterations,diastolic strain rate and exercise capacity in mild heart failure with preserved ejection fraction: a cardiovascular magnetic resonance study

Background

Heart failure (HF) is characterized by altered myocardial substrate metabolism which can lead to myocardial triglyceride accumulation (steatosis) and lipotoxicity. However its role in mild HF with preserved ejection fraction (HFpEF) is uncertain. We measured myocardial triglyceride content (MTG) in HFpEF and assessed its relationships with diastolic function and exercise capacity.

Methods

Twenty seven HFpEF (clinical features of HF, left ventricular EF >50%, evidence of mild diastolic dysfunction and evidence of exercise limitation as assessed by cardiopulmonary exercise test) and 14 controls underwent ¹H-cardiovascular magnetic resonance spectroscopy (¹H-CMRS) to measure MTG (lipid/water, %), ³¹P-CMRS to measure myocardial energetics (phosphocreatine-to-adenosine triphosphate - PCr/ATP) and feature-tracking cardiovascular magnetic resonance (CMR) imaging for diastolic strain rate.

Results

When compared to controls, HFpEF had 2.3 fold higher in MTG (1.45?±?0.25% vs. 0.64?±?0.16%, p?=?0.009) and reduced PCr/ATP (1.60?±?0.09 vs. 2.00?±?0.10, p?=?0.005). HFpEF had significantly reduced diastolic strain rate and maximal oxygen consumption (VO₂ max), which both correlated significantly with elevated MTG and reduced PCr/ATP. On multivariate analyses, MTG was independently associated with diastolic strain rate while diastolic strain rate was independently associated with VO₂ max.

Conclusions

Myocardial steatosis is pronounced in mild HFpEF, and is independently associated with impaired diastolic strain rate which is itself related to exercise capacity. Steatosis may adversely affect exercise capacity by indirect effect occurring via impairment in diastolic function. As such, myocardial triglyceride may become a potential therapeutic target to treat the increasing number of patients with HFpEF.

     

Cell Phone Internet Access,Online Sexual Solicitation,Partner Seeking,and Sexual Risk Behavior Among Adolescents

Archives of Sexual Behavior - Online partner seeking is associated with sexual risk behavior among young adults (specifically men who have sex with men), but this association has yet to be explored...     

Breathing retraining for asthma

Breathing retraining is used increasingly throughout the world by many patients with asthma in addition to their usual medical care. We undertook a systematic review of the literature in order to determine the effectiveness of breathing retraining in the management of asthma. Six randomised-controlled trials were identified that involved breathing retraining in asthma. Due to the variation in reported trial outcomes, limited reporting of study data and small number of included trials it was not possible to draw any firm conclusions as to its effectiveness. However, outcomes that were reported from individual trials do show that breathing retraining may have a role in the treatment and management of asthma. Further large-scale trials using breathing retraining techniques in asthma are required to address this important issue.     

Relationship between esophageal motility and transit in patients with type I diabetes mellitus

OBJECTIVES: Delayed esophageal transit and abnormal esophageal motility occur frequently in patients with long-standing diabetes mellitus. However, the relationship between transit and motility has not been assessed directly. The aim of this study was to investigate the patterns of esophageal motor function documented previously to have delayed esophageal emptying and esophageal transit in patients with insulin-dependent diabetes mellitus. METHODS: Concurrent esophageal manometry and radionuclide measurement of transit of liquids and solids were performed in 11 patients with insulin-dependent diabetes, 10 age-matched controls, and 11 young normal subjects. RESULTS: Patients with diabetes had a greater frequency of transit hold-up for solids (96%) than did older controls (65%) or young normals (42%) (p < 0.001), whereas the frequency of transit hold-up for liquid boluses was similar among the three groups (diabetics, 36%; older normals, 17%; young normals, 17%). The major mechanism responsible for bolus hold-up in diabetics was peristaltic failure (liquid, 52%; solid, 67%) and the level of hold-up coincided with the level of bolus hold-up for 10/11 liquid and 27/28 solid boluses. CONCLUSIONS: In insulin-dependent diabetes, retarded esophageal transit usually reflects either peristaltic failure or focal low-amplitude pressure waves.     

Identification of glycoprotein Ib as a target for autoantibody in idiopathic (autoimmune) thrombocytopenic purpura

An antibody (DIL) from a patient with idiopathic thrombocytopenic purpura (ITP) was shown to have autospecificity on the basis of reactions with autologous platelets that were identical to those obtained with platelets from normal subjects. DIL antibody also reacted strongly in an immunofluorescence test with platelets from a patient with Glanzmann's thrombasthenia, but failed to react with platelets from a patient with the Bernard-Soulier syndrome who was known to be deficient in glycoprotein Ib (GPIb). Purified GPIb and control platelets, but not Bernard-Soulier platelets, inhibited the lytic activity of DIL. Using the GPIb-specific monoclonal antibody AP1 and one-dimensional rocket electrophoresis into gels containing rabbit antihuman platelet membrane antibody, it was shown that staphylococcal protein A-Sepharose beads coated with DIL antibody selectively remove GPIb from solubilized platelet preparations. By crossed immunoelectrophoresis it was found that DIL recognizes a determinant on GPIb on the membrane side of the cleavage site of the platelet calcium- activated protease (calpain). These studies provide direct evidence for binding of a platelet autoantibody to a determinant on GPIb relatively close to the site of insertion of this protein into the platelet membrane.     

Acceptability of Smartphone Application-Based HIV Prevention Among Young Men Who Have Sex With Men

Young men who have sex with men (YMSM) are increasingly using mobile smartphone applications (“apps”), such as Grindr, to meet sex partners. A probability sample of 195 Grindr-using YMSM in Southern California were administered an anonymous online survey to assess patterns of and motivations for Grindr use in order to inform development and tailoring of smartphone-based HIV prevention for YMSM. The number one reason for using Grindr (29 %) was to meet “hook ups.” Among those participants who used both Grindr and online dating sites, a statistically significantly greater percentage used online dating sites for “hook ups” (42 %) compared to Grindr (30 %). Seventy percent of YMSM expressed a willingness to participate in a smartphone app-based HIV prevention program. Development and testing of smartphone apps for HIV prevention delivery has the potential to engage YMSM in HIV prevention programming, which can be tailored based on use patterns and motivations for use.