Submit a Letter to the Editor for:
J M Edelberg, W C Aird, R D Rosenberg
J Clin Invest. 1998;
101(2):337
doi:10.1172/JCI1330
Abstract |
Full text
|
PDF
C
ardiac pacemaking offers a unique opportunity for direct gene transfer into the heart. An experimental system was developed to assay the effects of transferring the human beta2 adrenergic receptor (beta2AR) under in vitro, ex vivo, and finally in vivo conditions. Constructs encoding either beta2AR or LacZ were used in chronotropy studies with isolated myocytes, and transplanted as well as endogenous murine hearts. Murine embryonic cardiac myocytes were transiently transfected with plasmid constructs. The total percentage of myocytes spontaneously contracting was greater in beta2AR transfected cells, as compared with control cells (67 vs. 42+/-5%). In addition, the percentage of myocytes with chronotropic rates > 60 beats per minute (bpm) was higher in the beta2AR population, as compared with control cells (37 vs. 15+/-5%). The average contractile rate was greater in the beta2AR transfected myocytes at baseline (71+/-14 vs. 50+/-10 bpm; P < 0.001) as well as with the addition of 10(-)3 M isoproterenol (98+/-26 vs. 75+/-18 bpm; P < 0.05). Based on these results, a murine neonatal cardiac transplantation model was used to study the ex vivo effects of targeted expression of beta2AR. The constructs were transfected into the right atrium of transplanted hearts. Injection of the beta2AR construct increased the heart rate by approximately 40% (224+/-37 vs. 161+/-42 bpm; P < 0.005). Finally, the constructs were tested in vivo with injection into the right atrium of the endogenous heart. These results were similar to the ex vivo data with injection of the beta2AR constructs increasing the endogenous heart rates by approximately 40%, as compared with control injected hearts (550+/-42 vs. 390+/-37 bpm; P < 0.05). These studies demonstrate that local targeting of gene expression may be a feasible modality to regulate the cardiac pacemaking activity.
Guidelines:
The Editorial Board will only consider letters that we deem relevant and of interest to our readers. We will not post data that have not been subjected to peer review, nor will we post letters that are essentially a reiteration of another letter. All accepted letters will be posted on our website within one week of acceptance. The Editors reserve the right to edit any letter for length, content, and clarity. Authors of all accepted letters will be asked to preview any changes. Authors will be notified by e-mail if their letters were not accepted. As this is a final decision, no appeals will be considered.
Specific requirements: All letters must be 400 words or fewer. You may enter the letter as plain text or HTML, if you wish. The author's name and e-mail address are required, and will be posted with the letter. All possible conflicts of interest must be noted, even if they are not posted. If you wish to include a figure (keep in mind that non-peer-reviewed data will not be posted), please contact the editor directly at editors@the-jci.org.
