PROCEEDINGS OF THE BALTIMORE SMOOTH MUSCLE MEETING: IDENTIFYING RESEARCH FRONTIERS AND PRIORITIES FOR THE LOWER URINARY TRACT GEORGE J. CHRIST* , † AND MONICA LIEBERT‡ From the Departments of Urology, and Physiology and Pharmacology, Wake Forest Institute for Regenerative Medicine, Wake Forest University (GJC), Winston-Salem, North Carolina, and Office of Research, American Urological Association (ML), Linthicum, Maryland ABSTRACT Purpose: The myocyte is a major parenchymal cell of the lower urinary tract (LUT) in men and women. Significant phenotypic diversity ensures that myocytes subserve their important role in the physiologically distinct tissues and organs of the LUT, including the ureters, bladder, urethra, prostate, penis, vagina and myometrium. Coordinated contraction and relaxation of myocytes is required for normal organ function, while alterations in myocyte structure/function are implicated in the etiology of various LUT diseases/disorders. LUT diseases/disorders will continue to increase in an ever aging American population. The purpose of the Baltimore Smooth Muscle Meeting was to begin to identify some research frontiers and priorities. Materials and Methods: A 1-day conference of some of the leading world experts in smooth muscle research was held at American Urological Association headquarters. These experts gave presentations in their areas of expertise and extensively discussed their work. This report details those interactions. Results: There is astonishing diversity in the contribution of the myocyte to LUT physiology and dysfunction. Novel tools, technologies and ideas have produced increased understanding and identified new frontiers. Conclusions: An improved understanding of urogenital myocyte physiology, function and dysfunction is required better to elucidate disease mechanisms and develop novel therapeutics. The First Annual Baltimore Smooth Muscle Meeting provided the first step in this direction. More coordinated LUT myocyte funding initiatives, the further development of research re- sources, tools and technologies, and exploration of the urogenital system as a model system for studying systems biology and integrative physiology are among the highest research priorities. KEY WORDS: urinary tract; urogenital system; muscle cells; muscle, smooth; physiopathology There are 2 types of muscle, namely striated muscle (car- diac and skeletal) and smooth muscle (visceral and vascular muscle, comprising the hollow organs/tubes of the body). Each contributes to urogenital function but this report fo- cuses exclusively on the latter, which is a major parenchymal cell in tissues/organs throughout the lower urinary tract (LUT). Unless otherwise specified, the term myocyte refers to the smooth muscle cell. Myocytes participate in the clinical sequelae of diverse LUT diseases/disorders. Examples include the detrusor over- activity linked to urgency and urge incontinence, the height- ened contraction and/or impaired relaxation of corporeal myocytes that predisposes to erectile dysfunction and the increased contractility involved in the dynamic component of benign prostatic hyperplasia and its complications (ie ure- thral obstruction). Altered myocyte function may also con- tribute to ureteral and urethral dysfunction. Therefore, dis- cerning the mechanistic basis for the contribution of myocytes to the pathophysiology of LUT dysfunction is a prerequisite to the improved understanding, diagnosis and treatment of these disease processes. Deconvoluting the physiological/pathophysiological char- acteristics of a cell type with the obvious phenotypic diversity of the urogenital myocyte will not be easy. Specifically the properties of the detrusor myocyte that contribute to the filling, storage and emptying of urine are understandably distinct from that of the corporeal myocyte, which serves a capacitive function in regulating blood flow to and from the penis. Moreover, these 2 myocytes are physiologically dis- tinct from myocytes of the ureters and urethra, which serve a conduit function to ensure the proper transit of urine. Myometrial and vaginal myocytes provide further contrast. These facts highlight the importance of clarifying the differ- ential development, physiology, biophysics and molecular ge- netics of these complex cells, and the impact of age, gender and disease thereupon. As a first step in this direction, on September 10, 2002 the first urological smooth muscle cell meeting was held, referred to as the Baltimore Smooth Muscle Meeting. The meeting was co-sponsored by the American Urological Association Office of Research (Monica Liebert, Ph.D., Director) and the Institute for Smooth Muscle Biology at Albert Einstein Col- lege of Medicine (George J. Christ, Ph.D., Former Director). Some of the leading world experts on myocyte biology gave Submitted for publication June 30, 2004. Supported by National Institutes of Health Grants R21DK57046 (JLL), DK57252, HL37956 and P50DK52620 (RM), DK53832, HL63722 and HL44455 (MTN), GM55263 (PRB), HL26043 (KK), PO1DK41315 and R37DK40569 (KMS), P50DK52620 (SKC), and DK55076, PO1DK60037 and R21DK60204 (GJC) (unless otherwise noted all grants are RO1s). * Correspondence: Department of Urology, and Physiology and Pharmacology, Cell/Tissue Physiology Program, Wake Forest Insti- tute for Regenerative Medicine, NRC Building, Room 110, Medical Center Blvd., Winston-Salem, North Carolina 27157. † Financial interest and/or other relationship with Ion Channel Innovations. ‡ Financial interest and/or other relationship with UroCore, Dabo, American Urological Association, Action to Cure Kidney Cause, In- terstitial Cystitis Association, Department of Defense and M. D. Anderson/University of Michigan. 0022-5347/05/1734-1406/0 Vol. 173, 1406–1409, April 2005 THE JOURNAL OF UROLOGY ® Printed in U.S.A. Copyright © 2005 by AMERICAN UROLOGICAL ASSOCIATION DOI: 10.1097/01.ju.0000152289.23797.75 1406