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Gut Reaction

Posted by on Friday, September 22, 2017 in Features, Homepage Highlights, Summer 2017 .

Photo by Daniel Dubois


Jennifer Fleming was 22 years old, just beginning a career in a new city, when she started having some troubling symptoms. A persistently upset stomach, diarrhea and a small amount of rectal bleeding launched a barrage of tests that ultimately ended in a diagnosis of ulcerative colitis, an inflammatory disease that damages the lining of the large intestine.

“At the time, it was very traumatic and scary, because I didn’t know what was going on,” says Fleming, now 31.

In the years since the diagnosis, her disease has been managed with a low amount of medication, and she’s had only occasional flares—bouts of pain and diarrhea—that required a steroid (prednisone) to bring them under control.

Then last year she had an extreme attack that caused diarrhea 40 to 60 times per day.

“It was really, really rough. I wasn’t even eating; I was just drinking water, and having a ton of blood loss and extreme dehydration,” she says. “The prednisone wasn’t working, and I was pretty discouraged during that time.”

Fleming is one of 70 million people in the United States affected by digestive diseases. Problems with our guts result in more than 48 million ambulatory care visits annually.

The No. 1 symptom, abdominal pain, prompted more than 27 million ambulatory care visits in 2010, with diarrhea, vomiting, nausea and bleeding rounding out the top five symptoms, according to the most recent review of the burden of gastrointestinal (GI), liver and pancreatic diseases published in the journal Gastroenterology.

“The morbidity of GI diseases as far as health care costs, time off of work and reduced quality of life is incredibly high, especially compared to other specialties,” says Richard Peek, M.D., Mina Cobb Wallace Professor of Immunology and director of the Division of Gastroenterology.


The inner tube

The human digestive system is a marvelously complex set of layered tubes working together to accomplish the essential tasks of digesting food, absorbing nutrients and expelling waste.

Stretching about 30 feet from end to end, the digestive tract includes specialized surfaces for nutrient absorption, a rich diversity of microbial species (the gut microbiota) and a nervous system all its own—the “second brain.” The neurons of the enteric nervous system, embedded within the walls of the digestive system, outnumber the neurons in the spinal cord.

Controlled by the enteric nervous system, muscular tubes generate peristalsis, the wave of contraction and relaxation that moves contents through the GI tract. Outside the tubes, the liver, pancreas and gallbladder join in to add secretions to the digestive mix.

All of this complexity fascinated Sara Horst, M.D., MPH, when she first learned about the digestive system during medical school.

Gastroenterologist Sara Horst, M.D., MPH. Photo by John Russell.

“The number of muscles and nerves that it takes to get food from your mouth through the GI tract and to actually absorb nutrients is pretty amazing,” says Horst, a gastroenterologist and assistant professor of Medicine.

“Most of the time, the process of food ingestion and nutrient absorption is seamless,” she says. “But when it’s not, it can impact a person’s life in enormous ways.”

The gut microbiota is thought to be key to maintaining a healthy digestive system, Peek says. Changes to the composition of the gut microbiota—perhaps because we’re living in more sterile environments or taking more antibiotics—result in dysbiosis, an unhealthy microbiota that may drive disease. But understanding cause and effect is difficult, he says.

“Does having a disease change your microbiota, or did an altered microbiota contribute to developing the disease? I think the more we understand the effects of the microbiota, the more we’re going to be able to manipulate it and potentially push people toward harboring a healthy microbiota,” Peek says.

The Vanderbilt Digestive Disease Center is a leader in studying and treating digestive diseases of all types. Specialty centers offer care for inflammatory bowel disease (IBD), hepatology, nutrition, chronic GI and swallowing and esophageal disorders.


Treating more than just the gut

IBD is a disease of chronic inflammation of part or all of the digestive tract. It primarily includes ulcerative colitis—inflammation and ulcers in the lining of the large intestine only—and Crohn’s disease—inflammation anywhere along the entire digestive tract—and affects about 1.6 million Americans, according to the Crohn’s & Colitis Foundation.

As it did for Fleming, “IBD causes abdominal pain and diarrhea and other problems at a time when people are starting to be productive as adults—most people are diagnosed in their 20s and 30s,” says David Schwartz, M.D., professor of Medicine and director of the Vanderbilt IBD Center, which currently cares for more than 7,000 patients from 27 states.

David Schwartz, M.D., director of the Vanderbilt IBD Center. Photo by Susan Urmy.

The chronic inflammation, which can range from mild to severe, can cause bowel obstructions, strictures and fistulas (abnormal openings or connections in the intestinal walls), and can increase the risk of colon cancer. IBD is not the same as IBS, irritable bowel syndrome, which does not involve inflammation or damage to the digestive tract.

The exact cause of IBD is unknown. It is an autoimmune disorder in which the patient’s own immune system attacks the gastrointestinal tract. It may reflect a dysregulated immune response to gut microbiota, and it appears to have a genetic component, although many people with IBD don’t have a family history of the disease.

Last year, when Fleming was experiencing the nonstop flares that did not respond to steroids, her gastroenterologist referred her to the Vanderbilt IBD Center to explore other treatment options.

“I was pleasantly surprised to find that the Vanderbilt center is so integrative—not only do you meet with a gastroenterologist, but you meet with a dietitian and a mental health counselor as well,” she says. “It’s been really helpful for me.”

The Vanderbilt IBD Center was one of the first in the nation to offer this type of multidisciplinary patient-centered approach for IBD, says Schwartz, who set up the model when he started the center in 2002. New patients see a team of providers: a gastroenterologist, a psychologist or clinical social worker, a dietitian and a pharmacist, if needed for medication counseling.

“The data are now catching up to what we’ve known in practice for a long time: if you treat both the medical side of things and the psychosocial side of things, patients do better overall,” Schwartz says.


Tailoring nutrition and psychological care

The psychological and nutritional support are key to the IBD center’s innovative health care model, says Horst, who treats patients at the center.

“We’re really aggressive about doing state-of-the-art medical management for patients with IBD, and at the same time we help patients recognize how stress, anxiety and depressive symptoms affect their disease, and how what they eat affects what happens in their gut,” Horst says. “I’ve learned that every single IBD patient probably needs a diet tailored to them.”

Dietitians in the center work with patients to develop a personalized diet.

Fleming says that she had tried many different diets over the course of her disease, even spending more than $1,000 one year seeing a naturalist-nutritionist.

“I think other nutritionists are well intended and have great information, but they don’t understand IBD,” she says. “It was freeing to meet with the dietitian at the IBD center. She (Pamela Duncan RD, LDN) understood specifically what my body needed with IBD and was able to walk me through strategies for the diet I could use during a flare and the diet I could transition to once in remission.”

Similarly, the psychologist and clinical social worker understand IBD and help patients manage mental health issues.

“Because she (Lindsey Franks, MSW) already had a baseline to understand where I was coming from, we could dive in to the emotional aspects of what it’s like living with a long-term disease that doesn’t technically have a cure yet,” Fleming says. “She was able to suggest really practical steps to help me manage on a daily basis and get through a time that was very difficult for me, when I was flaring pretty much nonstop for almost a year.”

The Vanderbilt IBD Center team also is conducting research to understand how psychological symptoms impact the disease process and management.

Recent studies have shown that up to 40 percent of patients with Crohn’s disease can present with depressive symptoms. Research at Vanderbilt and elsewhere suggests that patients who have depressive symptoms are more likely to have flares, may be more likely to require hospitalization or surgery and may be more likely to have severe disease.

“We’ve also shown that if a new patient has depressive symptoms, the likelihood that they will be non-compliant with their medicines goes way up,” Horst says.

Center investigators are exploring the factors that increase the risk of a patient having depressive symptoms. They have found that a history of psychiatric illness, smoking and use of narcotics increase risk for depressive symptoms, but the severity of a patient’s disease does not appear to increase risk, Horst says. The investigators also plan to study inflammatory markers in the blood and other aspects of the medical history.

“We want to identify who’s at risk for depressive symptoms so that we can tailor care for these patients and help them to be compliant in taking their medicines,” Horst says. “We have many therapeutic options that can really help patients, but if they don’t take the medicines, they don’t get better.”

Fleming values the team approach in the Vanderbilt IBD Center.

“You can really sense there’s genuine care and concern for the patients. They’re very thorough and detail-oriented in looking after their patients and thinking of things so I don’t have to, which is refreshing,” she says. “I really appreciate how integrative the center is, how they are able to treat me as a whole person and not just my colon.”