Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical therapeutic systems
Reexamination Certificate
2002-03-27
2004-11-30
Jastrzab, Jeffrey R. (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical therapeutic systems
Reexamination Certificate
active
06826428
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to gastrointestinal electrical stimulation, and more particularly to methods for regulating gastrointestinal action, reducing weight, providing electrical field stimulation to a gastrointestinal organ, providing electrical potential gradient in a gastrointestinal organ, stimulating the vagus nerve, and placing a device in the gastrointestinal tract or wall.
BACKGROUND OF THE INVENTION
Throughout this application various publications are referenced, many in parenthesis. Full citations for each of these publications are provided at the end of the Detailed Description and throughout the Detailed Description. The disclosures of each of these publications in their entireties are hereby incorporated by reference in this application.
Motility is one of the most critical physiological functions of the human gut. Without coordinated motility, digestion and absorption of dietary nutrients could not take place. To accomplish its functions effectively, the gut needs to generate not just simple contractions but contractions that are coordinated to produce transit of luminal contents (peristalsis). Thus, coordinated gastric contractions are necessary for the emptying of the stomach. The patterns of gastric motility are different in the fed state and the fasting state (Yamada et al. 1995). In the fed state, the stomach contracts at its maximum frequency, 3 cycles/min (cpm) in humans and 5 cpm in dogs. The contraction originates in the proximal stomach and propagates distally toward the pylorus. In healthy humans, the ingested food is usually emptied by 50% or more at 2 hours after the meal and by 95% or more at 4 hours after the meal (Tougas et al. 2000). When the stomach is emptied the pattern of gastric motility changes. The gastric motility pattern in the fasting state undergoes a cycle of periodic fluctuation divided into three phases: phase I (no contractions, 40-60 minutes), phase II (intermittent contractions, 20-40 minutes) and phase III (regular rhythmic contractions, 2-10 minutes).
Gastric motility (contractile activity) is in turn regulated by myoelectrical activity of the stomach. Gastric myoelectrical activity consists of two components, slow waves and spike potentials (Chen and McCallum 1995). The slow wave is omnipresent and occurs at regular intervals whether or not the stomach contracts. It originates in the proximal stomach and propagates distally toward the pylorus. The gastric slow wave determines the maximum frequency, propagation velocity and propagation direction of gastric contractions. When a spike potential (similar to an action potential), is superimposed on the gastric slow wave a strong lumen-occluded contraction occurs. The normal frequency of the gastric slow wave is about 3 cpm in humans and 5 cpm in dogs. A noninvasive method similar to electrocardiography, called electrogastrography, has been developed and applied to detect gastric slow waves using abdominal surface electrodes (Chen and McCallum 1995).
Abnormalities in gastric slow waves lead to gastric motor disorders and have been frequently observed in patients with functional disorders of the gut, such as gastroparesis, functional dyspepsia, anorexia and etc. (Chen and McCallum 1995). Gastric myoelectrical abnormalities include uncoupling and gastric dysrhythmia and can lead to significant impairment in gastric emptying (Lin et al. 1998; Chen et al. 1995a; Telander et al. 1978; You and Chey 1985; Chen and McCallum 1993). Tachygastria (an abnormally high frequency of the gastric slow wave) is known to cause gastric hypomotility (Lin et al. 1998; Chen et al. 1995a; Telander et al. 1978; You and Chey 1985; Chen and McCallum 1993).
Gastric emptying plays an important role in regulating food intake. Several studies have shown that gastric distention acts as a satiety signal to inhibit food intake (Phillips and Powley 1996) and rapid gastric emptying is closely related to overeating and obesity (Duggan and Booth 1986). In a study of 77 subjects composed of 46 obese and 31 age-, sex-, and race-matched nonobese individuals, obese subjects were found to have a more rapid emptying rate than nonobese subjects (Wright et al. 1983). Obese men were found to empty much more rapidly than their nonobese counterparts. It was concluded that the rate of solid gastric emptying in the obese subjects is abnormally rapid. Although the significance and cause of this change in gastric emptying remains to be definitively established, it has been shown that several peptides, including cholecystokinin (CCK) and corticotropin-releasing factor (CRF), suppress feeding and decrease gastric transit. The inhibitory effect of peripherally administered CCK-8 on the rate of gastric emptying contributes to its ability to inhibit food intake in various species (Moran and McHugh 1982). CRF is also known to decrease food intake and the rate of gastric emptying by peripheral injection (Sheldon et al. 1990). More recently, it was shown that in ob/ob mice (a genetic model of obesity), the rate of gastric emptying was accelerated compared with that in lean mice (Asakawa et al. 1999). Urocortin, a 40-amino acid peptide member of the CRF family, dose-dependently and potently decreased food intake and body weight gain as well as the rate of gastric emptying, in ob/ob mice. This suggests that rapid gastric emptying may contribute to hyperphagia and obesity in ob/ob mice and opens new possibilities for the treatment of obesity.
There have been a number of reports on gastrointestinal electrical stimulation for the treatment of gastrointestinal motility disorders in both dogs and humans (U.S. Pat. Nos. 5,423,872, 5,690,691, and 5,836,994; PCT International Publication No. WO 99/30776; Bellahsene et al. 1992; Mintchev et al. 1998; Mintchev et al. 1999; Mintchev et al. 2000; Chen et al. 1998; Chen et al. 1995c). These disorders are characterized by poor contractility and delayed emptying (by contrast with obesity) and the aim of electrical stimulation in this setting is to normalize the underlying electrical rhythm and improve these parameters. In general, this is done by antegrade or forward gastric (or intestinal) stimulation.
Previous work on antegrade gastrointestinal stimulation has been focused on its effects on a) gastric myoelectrical activity, b) gastric motility, c) gastric emptying, and d) gastrointestinal symptoms (Lin et al. 1998; Eagon and Kelly 1993; Hocking et al. 1992; Lin et al. 2000a; McCallum et al. 1998; Miedema et al. 1992; Qian et al. 1999; Abo et al. 2000; Bellahsene et al. 1992). These studies have conclusively shown that entrainment of gastric slow waves is possible using an artificial pacemaker. Recent studies have indicated that such entrainment is dependent on certain critical parameters, including the width and frequency of the stimulation pulse (Lin et al. 1998). It has also been shown that antegrade intestinal electrical stimulation can entrain intestinal slow waves using either serosal electrodes (Lin et al. 2000a) or intraluminal ring electrodes (Bellahsene et al. 1992).
Obesity is one of the most prevalent public health problems in the United States. According to the National Health and Nutrition Examination Survey, “overweight” (body mass index or BMI=25.0-29.9 kg/m
2
) adults now represent 59.4% of the male and 50.7% of the female population in this country, totaling more than 97 million people. The corresponding figures for “obesity” (BMI≧30) are about 19.5% for men and 25% for women, involving a total of almost 40 million people. “Morbid obesity” or clinically severe obesity (BMI≧40 or >100 lbs over normal weight) affects more than 15 million Americans (Kuczmarski et al. 1994; Troiano et al. 1995; Flegal et al. 1998; Kuczmarski et al. 1997). The treatment of obesity and its primary comorbidities costs the US healthcare system more than $100 billion each year (Klein 2000; Martin et al. 1995; Colditz 1992; Wolf and Colditz 1998); in addition, consumers spend in excess of $33 billion annually on weight-reduction products and services (House Co
Chen Jiande
Pasricha Pankaj Jay
Jastrzab Jeffrey R.
Rogalskyj & Weyand LLP
The Board of Regents of the University of Texas System
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