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(Circulation. 2000;101:e194.)
© 2000 American Heart Association, Inc.

Circulation Electronic Pages

Is Leptin Involved in the Signaling Cascade After Myocardial Ischemia and Reperfusion?

Gema Frühbeck, RNutr, MD, PhD; Javier Salvador, MD, PhD

Department of Endocrinology, Clínica Universitaria, University of Navarra, Pamplona, Spain

	Introduction

 
To the Editor:

We read with great interest the elegant study by Chandrasekar et al¹ about the upregulation of CCAAT/enhancer binding protein, interleukin-6, the interleukin-6 receptor, and the signal transducer gp130 during reperfusion after a brief period of myocardial ischemia. The rapid and sustained production of interleukin-6 and the concomitant expression of the interleukin-6 receptor and gp130 suggest that these factors may participate in a local inflammatory cascade after myocardial ischemia and reperfusion. We approach this finding from a complementary point of view and comment on the possible involvement of leptin in the signaling cascade of postischemic myocardium.

The ob gene product, also known as leptin, was discovered because of its very specific biological action: the ability to regulate body weight and appetite.² Interestingly, leptin has a structure similar to that of the family of helical cytokines, which includes interleukins. Many cytokines, which were originally isolated on the basis of particular biological actions, have subsequently been shown to be capable of stimulating a variety of biological responses in a wide spectrum of cell types. Thus, leptin shares with other cytokines an extreme functional pleiotropy, and it is involved in quite diverse physiological functions, such as reproduction, hematopoiesis, immunity, and angiogenesis.^{2 3}

The functional leptin receptors (OB-R), which have a widespread distribution, including the myocardium, belong to the class I cytokine receptor family.² The extracellular and cytoplasmic regions of OB-R and gp130 possess conserved motifs and are closely related to each other. OB-R and gp130 seem to mediate overlapping but distinct cytoplasmic . . . [Full Text of this Article]

Bysani Chandrasekar, PhD; Donald H. Mitchell, BS; James T. Colston, PhD; Gregory L. Freeman, MD

Medicine/Cardiology, The University of Texas Health Science Center and Audie L. Murphy Memorial Veterans Hospital, San Antonio, Texas