First-in-man trial of b3-adrenoreceptor agonist treatment in chronic heart failure – impact on diastolic function

Background

Diastolic dysfunction (DD) in heart failure (HF) is associated with increased myocardial cytosolic calcium, and calcium-efflux via the sodium-calcium-exchanger depends on the sodium gradient. Beta-3-adrenoceptor (β3-AR)-agonist lowers cytosolic sodium and has been shown to reverse organ congestion.

Purpose

To assess whether β3-AR-agonist treatment improves DD.

Methods

In a first-in-man randomized controlled, double-blind trial, we assigned 70 patients with HF with reduced ejection fraction (HFrEF) (NYHA II–III) and LVEF <40% to receive mirabegron (300 mg/day) or placebo for 6 months, in addition to recommended HF-therapy. Patients were assessed with echocardiography and cardiac computed tomography (CCT) at baseline and follow-up. DD was graded according to the current American/European guidelines.

Results

Baseline and follow-up echocardiographic data were available in 57 patients (59±11 years, 88% male, 49% ischemic heart disease). Baseline LVEF was 34%±8%. No significant change in DD grade was found between the groups at follow-up, p=0.72. Neither was there any clinical differences in any singular diastolic parameters within or between groups by echocardiography (E/e' placebo: 13.3±6.9 to 12.6±5.1, p=0.19 vs. mirabegron: 12.0±5.7 to 12.8±7.9, p=0.67, mean difference 1.12 [95% CI −1.68 to 4.3], p=0.37), or CCT (left atrial max volume index: between group mean difference 0.2 [95% CI −6.2 to 5.6] ml/m2, p=0.91).

Conclusions

In patients with HFrEF, no improvement nor worsening in DD gradings or singular diastolic parameters after β3-AR stimulation compared to placebo were identified. The findings add to previous literature questioning the role of impaired Na+-Ca2+ mediated Ca2+ export as a major culprit in DD.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): The Heart Centre Research Foundation, RigshospitaletThe Novo Nordic Foundation

Accumulation of dietary cadmium (Cd) in rabbit tissues and excretions: a comparison of lettuce amended with soluble Cd salt and lettuce with plant-incorporated Cd

Quantifying the transfer of Cd from foods to mammalian target organs is key to estimating the health risk from this exposure; however, the bioaccumulation of Cd from foods is modified by many dietary components. Studies of dietary Cd absorption would be simpler if it were known that Cd added to foods as a soluble salt was as bioavailable as Cd incorporated during growth of the food species. Rabbits were fed, for 16 d, fresh lettuce containing cadmium incorporated into the lettuce during growth or added to the lettuce before feeding, or lettuce with no Cd but soluble Cd administered to the animals by gavage. There was a marked positive relationship between increased Cd dose and its accumulation in kidney; the slopes for the gavage and added treatments were not clearly different from the incorporated treatment; liver data were highly variable. In a 10-wk study of Cd-incorporated and -amended lettuce diets, for the incorporated and control diets there was less Cd accumulation in the kidneys, but not liver, per unit cumulative dose, than for the amended diet. Cd accumulation in the small intestine and Cd concentration in feces, both per unit daily dose, were smaller for the incorporated than for the control and amended diets; Cd concentrations in bile, urine, and serum, per unit daily dose, were higher in the control diet than values in the amended diet, which were higher than the incorporated diet. These differences could not be accounted for by variation in Fe or Zn contents of the diets. Thus, data suggest that Cd-amended diets overestimate bioaccumulation in kidney, an important target organ, by up to one-third, and that studies of short duration are not adequate to evaluate Cd bioavailability from food.

Feasibility of immediate breast reconstruction for locally advanced breast cancer

BACKGROUND

Immediate breast reconstruction (IBR) has been considered contraindicated for patients with locally advanced breast cancer (LABC). Our goal was to determine whether IBR resulted in delayed postoperative chemotherapy, increased postoperative complications, or increased risk of recurrent disease.

METHODS

A prospective database of 540 modified radical mastectomies performed with IBR between 1990 and 1993 identified 50 patients with LABC. Postoperative management and outcome were compared to that of 72 patients undergoing modified radical mastectomy without IBR treated on a standardized LABC protocol using preoperative chemotherapy, postoperative chemotherapy, and radiotherapy during the same time period.

RESULTS

Results were evaluated by chi2 analysis. The median ages for the patients with IBR versus those not undergoing IBR were 44 and 46 years, respectively. The stage distribution for the IBR patients versus patients not undergoing IBR was as follows: IIB, 46% versus 17%; IIIA, 44% versus 39%; and IIIB, 10% versus 44%. The types of IBR were transverse rectus abdominis myocutaneous (TRAM) flap (68%), latissimus dorsi flap (2%), and implants (30%). Chemotherapy was given to all IBR patients: 24% preoperatively and 96% postoperatively. Radiotherapy was used in 40%. Four postoperative complications (8%) necessitated prolongation of hospitalization, including two patients requiring surgical debridement for partial flap loss; there were no complete flap losses. The incidences of major and minor wound complications in the group not undergoing IBR were 7% and 4%, respectively. Of the 15 patients receiving implant reconstruction, 7 (47%) required subsequent implant removal because of contractures or infections. The median interval between surgery and postoperative chemotherapy was 35 days for the IBR patients and 21 days for the patients not undergoing IBR. This difference was marginally significant (P =.05). With a median follow-up of 58.4 months, no significant differences in local or distant relapse rates were detected.

CONCLUSIONS

IBR can be performed with low morbidity in patients with LABC. Use of autogenous tissue is preferable because of poor results with implants. IBR is associated with somewhat longer intervals to resumption of postoperative chemotherapy, but this does not appear to be clinically significant-the local and distant relapse rates are similar for LABC patients undergoing modified radical mastectomy with or without IBR.

Culture-positive Bartonella quintana endocarditis

A 50-year-old alcoholic man with a 1-year history of pyrexia of unknown origin was admitted with symptoms of endocarditis. Large vegetations on his mitral and aortic valve were found on echocardiography. Using the Bactec 9240 system. Bartonella quintana could be grown from two culture sets of blood collected before the start of antimicrobial therapy. This is the first case report of culture-proven bartonella infection in the UK. and is noteworthy because Bartonella quintana was detected in conventional blood culture systems after prolonged incubation.