imally invasive aortic banding in mice: effects of altered cardiomyocyte insulin signaling during pressure overload. Am J Physiol Heart Circ Physiol 285: H1261-H1269, 2003. First published May 8, 2003 10.1152/ajpheart.00108. 2003.-We developed a minimally invasive method for producing left ventricular (LV) pressure overload in mice. With the use of this technique, we quickly and reproducibly banded the transverse aorta with low surgical morbidity and mortality. Minimally invasive transverse aortic banding (MTAB) acutely and chronically increased LV systolic pressure, increased heart weight-to-body weight ratio, and induced myocardial fibrosis. We used this technique to determine whether reduced insulin signaling in the heart altered the cardiac response to pressure overload. Mice with cardiac myocyte-restricted knockout of the insulin receptor (CIRKO) have smaller hearts than wild-type (WT) controls. Four weeks after MTAB, WT and CIRKO mice had comparably increased LV systolic pressure, increased cardiac mass, and induction of mRNA for ␤-myosin heavy chain and atrial natriuretic factor. However, CIRKO hearts were more dilated, had depressed LV systolic function by echocardiography, and had greater interstitial fibrosis than WT mice. Expression of connective tissue growth factor was increased in banded CIRKO hearts compared with WT hearts. Thus lack of insulin signaling in the heart accelerates the transition to a more decompensated state during cardiac pressure overload. The use of the MTAB approach should facilitate the study of the pathophysiology and treatment of pressureoverload hypertrophy.hypertrophy; contractility; fibrosis THE ABILITY TO MANIPULATE gene expression in mice has contributed greatly to the study of many diseases. In terms of the heart, the response of genetically altered animals to increased cardiac work (e.g., pressure overload) is of particular interest. Rockman and colleagues (33) pioneered a model of transverse aortic constriction in the mouse. The use of this model has provided significant insight into the cellular and molecular pathways responsible for the development of left ventricular (LV) hypertrophy (LVH). Although transverse aortic constriction in mice is now done routinely by a number of groups, the technical difficulty of the surgical procedure has limited the availability of this model.Previously published methods for the creation of transverse aortic constriction in mice require microsurgical skills and the ability to provide mechanical ventilation when the thorax is entered. The requirement for tracheal intubation and low-volume, high-rate mechanical ventilation mandates additional time and expense associated with these procedures. Moreover, inflammatory reactions within the chest may complicate the analyses of cardiac function and pathology. Herein, we report a minimally invasive transverse aortic banding (MTAB) procedure in mice that obviates the need for providing mechanical ventilation because the pleural space is not entered. The procedure can be performed rapidly and...

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Although patients' satisfaction may be high after restorative proctocolectomy the functional results are still far from perfect. Increased bowel frequency and imperfection in continence are common. Pouch volume and anal sphincter status are important determinants for the outcome. The aim of the present study was to evaluate if balloon dilatation of the pouch and sphincter biofeedback training might improve the results. Forty patients with an ileo-pouch anal anastomosis were randomized into a control and a treatment group. During the interval with a diverting ileostomy, patients in the latter group were subjected to balloon dilatation of the pouch and sphincter biofeedback training by using a manovolumetric technique. All patients were functionally assessed and anorectal manovolumetry performed preoperatively and at regular intervals postoperatively. Follow-up time was at least 12 months. Immediately before ileostomy take down patients in the treatment group showed a significant initial increase in pouch compliance compared with controls. However, a rapid and pronounced increase in pouch volume occurring after ileostomy closure in the control group equalized this initial difference. Anal resting tone and maximum squeezing capacity were at all intervals similar in the two groups. Bowel frequency per 24 h was similar and mucus soiling occurred to a similar extent in both groups, and the overall functional result as assessed according to a scoring system was equal at each interval. Balloon dilatation of the pouch and sphincter exercises appear not to be essential measures in these patients.

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