Effect of Extent of Resection on Intestinal Muscle Adaptation

Smooth Muscle Cell Hypertrophy and Hyperplasia in the Partially Obstructed Gut of the Rat: A Quantitative Evaluation

“…Data presented in this study are in line with those of the literature that demonstrated the relevant potentiality for cell proliferation of smooth muscle in various organs and species of mature animals, in relation to different experimental and/or pathological conditions [Cussen and Tymms, 1972;Gee and Kiviat, 1975;Gabella, 1990;Nguyen et al, 1996;VinterJensen et al, 1997]. Recent quantitative data on smooth muscle hyperplasia suggested that the degree of this phenomenon could be, in some conditions, even more pronounced than the coexisting cell hypertrophy [Nguyen et al, 1996;Vinter-Jensen et al, 1997]. In relation to this issue, data of the present study showed that the relationship among the four different morphological parameters that were investigated is different in upstream and downstream segments.…”

“…Further analysis confirmed the persistence of the proliferative capacity of the adult's smooth muscle in the ureter of other species as a consequence of an obstruction [Gee and Kiviat, 1975] and, recently, as a conSmooth Muscle Cell Hypertrophy and Hyperplasia in the Partially Obstructed Gut of the Rat: A Quantitative Evaluation sequence of systemic treatment with epidermal growth factor [Vinter-Jensen et al, 1997]. In addition, the capacity for cell proliferation in the smooth muscle has been assessed in other organs under particular experimental and/or pathological conditions, such as vessels of hypertensive rats [Owens and Reidy, 1985;Owens, 1985Owens, , 1989, myometrium during treatment with estrogen [Martin et al, 1973], airway smooth muscle underlying bronchial asthma [Page and Coyle, 1989;Ebina et al, 1993], smooth muscle at various levels of the gastroenteric system, after resection [Jurukova and Atanassova, 1974;Nguyen et al, 1996] and after partial obstruction [Gabella, 1975[Gabella, , 1979[Gabella, , 1990Brossa et al, 1992a, Canavese et al, 1992. In the context of the gastroenteric system, the subtotal stenosis surgically induced in the small intestine provides a particularly suitable experimental condition for the study of tissue and cell modification which characterizes a smooth muscle volume increase for three main reasons: (1) surgery is easy and rapid; (2) the model provides an internal control represented by intestinal loops downstream from the stenosis; in fact, this tract does not show hypotrophy since, if surgery is correctly done, intestinal transit is slowed down without being completely interrupted, and (3) hypertrophy occurs in a relatively brief lapse of time (a few days in the rat).…”

Smooth muscle overexpression of IGF-I induces a novel adaptive response to small bowel resection

“…Postresection intestinal adaptation characteristically involves all layers of the intestinal wall. More specifically, SMC hyperplasia has been well documented after intestinal resection in rats (16,21) and dogs (19). Hyperplasia may occur in face of no change in muscle thickness, possibly because of increased caliber (21) and/or length of the intestine.…”

“…Although the resection-induced adaptation response has classically been acknowledged to involve all layers of the intestinal wall (7,33), the bulk of research has primarily focused on morphological and functional alterations within the mucosa. However, hyperplasia of the muscular layers of the bowel wall has also been described after intestinal resection (16,19). The significance of these muscular changes is presently not well understood but may serve to influence postresection intestinal motility, thereby affecting the capacity for luminal absorption and/or digestion.…”

Differential Effect of Growth Factors on Intestinal Wall Components

“…Such an adaptive response in hydroxyproline content of the intestine was reduced, even below that of normal unoperated intestine. Graham et al the muscle layers occurs following intestinal resection [21]. Increased collagen synthesis by intestinal smooth [22] found that EGF does not stimulate collagen synthesis in smooth muscle cells in vitro.…”