Leptin and other pro inflammatory biomakers for chronic fatigue syndrome

Researchers identify biomarkers associated with chronic fatigue syndrome severity

Stanford investigators used high-throughput analysis to link inflammation to chronic fatigue syndrome, a difficult-to-diagnose disease with no known cure.

Man in a lab coat sitting near a microscope with a woman in a lab coat in the background

Jose Montoya and his colleagues have found evidence inflammation may be the culprit behind chronic fatigue syndrome, a disease with no known cure.
Steve Fisch

Researchers at the Stanford University School of Medicine have linked chronic fatigue syndrome to variations in 17 immune-system signaling proteins, or cytokines, whose concentrations in the blood correlate with the disease’s severity.

The findings provide evidence that inflammation is a powerful driver of this mysterious condition, whose underpinnings have eluded researchers for 35 years.

The findings, described in a study published online July 31 in the Proceedings of the National Academy of Sciences, could lead to further understanding of this condition and be used to improve the diagnosis and treatment of the disorder, which has been notably difficult.

More than 1 million people in the United States suffer from chronic fatigue syndrome, also known as myalgic encephomyelitis and designated by the acronym ME/CFS. It is a disease with no known cure or even reliably effective treatments. Three of every four ME/CFS patients are women, for reasons that are not understood. It characteristically arises in two major waves: among adolescents between the ages of 15 and 20, and in adults between 30 and 35. The condition typically persists for decades.

“Chronic fatigue syndrome can turn a life of productive activity into one of dependency and desolation,” said Jose Montoya, MD, professor of infectious diseases, who is the study’s lead author. Some spontaneous recoveries occur during the first year, he said, but rarely after the condition has persisted more than five years.

The study’s senior author is Mark Davis, PhD, professor of immunology and microbiology and director of Stanford’s Institute for Immunity, Transplantation and Infection.

‘Solid basis for a diagnostic blood test’

“There’s been a great deal of controversy and confusion surrounding ME/CFS — even whether it is an actual disease,” said Davis. “Our findings show clearly that it’s an inflammatory disease and provide a solid basis for a diagnostic blood test.”

Many, but not all, ME/CFS patients experience flulike symptoms common in inflammation-driven diseases, Montoya said. But because its symptoms are so diffuse —sometimes manifesting as heart problems, sometimes as mental impairment nicknamed “brain fog,” other times as indigestion, diarrhea, constipation, muscle pain, tender lymph nodes and so forth — it often goes undiagnosed, even among patients who’ve visited a half-dozen or more different specialists in an effort to determine what’s wrong with them.

Mark Davis

Mark Davis

Montoya, who oversees the Stanford ME/CFS Initiative, came across his first ME/CFS patient in 2004, an experience he said he’s never forgotten.

“I have seen the horrors of this disease, multiplied by hundreds of patients,” he said. “It’s been observed and talked about for 35 years now, sometimes with the onus of being described as a psychological condition. But chronic fatigue syndrome is by no means a figment of the imagination. This is real.”

Antivirals, anti-inflammatories and immune-modulating drugs have led to symptomatic improvement in some cases, Montoya said. But no single pathogenic agent that can be fingered as the ultimate ME/CFS trigger has yet been isolated, while previous efforts to identify immunological abnormalities behind the disease have met with conflicting and confusing results.

Still, the sporadic effectiveness of antiviral and anti-inflammatory drugs has spurred Montoya to undertake a systematic study to see if the inflammation that’s been a will-o’-the-wisp in those previous searches could be definitively pinned down.

To attack this problem, he called on Davis, who helped create the Human Immune Monitoring Center. Since its inception a decade ago, the center has served as an engine for large-scale, data-intensive immunological analysis of human blood and tissue samples. Directed by study co-author Holden Maecker, PhD, a professor of microbiology and immunology, the center is equipped to rapidly assess gene variations and activity levels, frequencies of numerous immune cell types, blood concentrations of scores of immune proteins, activation states of intercellular signaling models, and more on a massive scale.

Finding patterns

This approach is akin to being able to look for and find larger patterns — analogous to whole words or sentences — in order to locate a desired paragraph in a lengthy manuscript, rather than just try to locate it by counting the number of times in which the letter A appears in every paragraph.

The scientists analyzed blood samples from 192 of Montoya’s patients, as well as from 392 healthy control subjects. The average age of patients and controls was about 50. Patients’ average duration of symptoms was somewhat more than 10 years.

Importantly, the study design took into account patients’ disease severity and duration. The scientists found that some cytokine levels were lower in patients with mild forms of ME/CFS than in the control subjects, but elevated in ME/CFS patients with relatively severe manifestations. Averaging the results for patients versus controls with respect to these measures would have obscured this phenomenon, which Montoya said he thinks may reflect different genetic predispositions, among patients, to progress to mild versus severe disease.

I have seen the horrors of this disease, multiplied by hundreds of patients.

When comparing patients versus control subjects, the researchers found that only two of the 51 cytokines they measured were different. Tumor growth factor beta was higher and resistin was lower in ME/CFS patients. However, the investigators found that the concentrations of 17 of the cytokines tracked disease severity. Thirteen of those 17 cytokines are pro-inflammatory.

TGF-beta is often thought of as an anti-inflammatory rather than a pro-inflammatory cytokine. But it’s known to take on a pro-inflammatory character in some cases, including certain cancers. ME/CFS patients have a higher than normal incidence of lymphoma, and Montoya speculated that TGF-beta’s elevation in ME/CFS patients could turn out to be a link.

One of the cytokines whose levels corresponded to disease severity, leptin, is secreted by fat tissue. Best known as a satiety reporter that tells the brain when somebody’s stomach is full, leptin is also an active pro-inflammatory substance. Generally, leptin is more abundant in women’s blood than in men’s, which could throw light on why more women than men have ME/CFS.

More generally speaking, the study’s results hold implications for the design of future studies of disease, including clinical trials testing immunomodulatory drugs’ potential as ME/CFS therapies.

“For decades, the ‘case vs. healthy controls’ study design has served well to advance our understanding of many diseases,” Montoya said. “However, it’s possible that for certain pathologies in humans, analysis by disease severity or duration would be likely to provide further insights.”

Other Stanford co-authors of the study are clinical research coordinator Jill Anderson; Tyson Holmes, PhD, senior research engineer at the Institute for Immunity, Transplantation and Infection; Yael Rosenberg-Hasson, PhD, immunoassay and technical director at the institute; Cristina Tato, PhD, MPH, research and science analyst at the institute; former study coordinator Ian Valencia; and Lily Chu, MSHS, a board member of the Stanford University ME/CFS Initiative.

The study was funded by the National Institutes of Health (grant U19AI057229), the Stanford ME/CFS Initiative Fund and an anonymous donor.

Stanford’s departments of Medicine and of Microbiology and Immunology also supported the work.

Chronic Fatigue Syndrome Is Not in Your Head, It’s in Your Gut

Summary: Researchers have identified biomarkers for chronic fatigue syndrome in gut bacteria and in inflammatory microbial agents in the blood.

Source: Cornell University.

Physicians have been mystified by chronic fatigue syndrome, a condition where normal exertion leads to debilitating fatigue that isn’t alleviated by rest. There are no known triggers, and diagnosis requires lengthy tests administered by an expert.

Now, for the first time, Cornell University researchers report they have identified biological markers of the disease in gut bacteria and inflammatory microbial agents in the blood.

In a study published June 23 in the journal Microbiome, the team describes how they correctly diagnosed myalgic encephalomyeletis/chronic fatigue syndrome (ME/CFS) in 83 percent of patients through stool samples and blood work, offering a noninvasive diagnosis and a step toward understanding the cause of the disease.

“Our work demonstrates that the gut bacterial microbiome in chronic fatigue syndrome patients isn’t normal, perhaps leading to gastrointestinal and inflammatory symptoms in victims of the disease,” said Maureen Hanson, the Liberty Hyde Bailey Professor in the Department of Molecular Biology and Genetics at Cornell and the paper’s senior author. “Furthermore, our detection of a biological abnormality provides further evidence against the ridiculous concept that the disease is psychological in origin.”

“In the future, we could see this technique as a complement to other noninvasive diagnoses, but if we have a better idea of what is going on with these gut microbes and patients, maybe clinicians could consider changing diets, using prebiotics such as dietary fibers or probiotics to help treat the disease,” said Ludovic Giloteaux, a postdoctoral researcher and first author of the study.

In the study, Ithaca campus researchers collaborated with Dr. Susan Levine, an ME/CFS specialist in New York City, who recruited 48 people diagnosed with ME/CFS and 39 healthy controls to provide stool and blood samples.

The researchers sequenced regions of microbial DNA from the stool samples to identify different types of bacteria. Overall, the diversity of types of bacteria was greatly reduced and there were fewer bacterial species known to be anti-inflammatory in ME/CFS patients compared with healthy people, an observation also seen in people with Crohn’s disease and ulcerative colitis.

Image shows gut bacteria.

At the same time, the researchers discovered specific markers of inflammation in the blood, likely due to a leaky gut from intestinal problems that allow bacteria to enter the blood, Giloteaux said.

Bacteria in the blood will trigger an immune response, which could worsen symptoms.

The researchers have no evidence to distinguish whether the altered gut microbiome is a cause or a whether it is a consequence of disease, Giloteaux added.

In the future, the research team will look for evidence of viruses and fungi in the gut, to see whether one of these or an association of these along with bacteria may be causing or contributing to the illness.

ABOUT THIS NEUROLOGY RESEARCH ARTICLE

Funding: The study was funded by the National Institutes of Health.

Source: Melissa Osgood – Cornell University
Image Source: This NeuroscienceNews.com image is in the public domain.
Original Research: Full open access research for for “Reduced diversity and altered composition of the gut microbiome in individuals with myalgic encephalomyelitis/chronic fatigue syndrome” by Ludovic Giloteaux, Julia K. Goodrich, William A. Walters, Susan M. Levine, Ruth E. Ley and Maureen R. Hanson in Microbiome. Published online June 23 2016 doi:10.1186/s40168-016-0171-4

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Abstract

Reduced diversity and altered composition of the gut microbiome in individuals with myalgic encephalomyelitis/chronic fatigue syndrome

Background
Gastrointestinal disturbances are among symptoms commonly reported by individuals diagnosed with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). However, whether ME/CFS is associated with an altered microbiome has remained uncertain. Here, we profiled gut microbial diversity by sequencing 16S ribosomal ribonucleic acid (rRNA) genes from stool as well as inflammatory markers from serum for cases (n = 48) and controls (n = 39). We also examined a set of inflammatory markers in blood: C-reactive protein (CRP), intestinal fatty acid-binding protein (I-FABP), lipopolysaccharide (LPS), LPS-binding protein (LBP), and soluble CD14 (sCD14).

Results
We observed elevated levels of some blood markers for microbial translocation in ME/CFS patients; levels of LPS, LBP, and sCD14 were elevated in ME/CFS subjects. Levels of LBP correlated with LPS and sCD14 and LPS levels correlated with sCD14. Through deep sequencing of bacterial rRNA markers, we identified differences between the gut microbiomes of healthy individuals and patients with ME/CFS. We observed that bacterial diversity was decreased in the ME/CFS specimens compared to controls, in particular, a reduction in the relative abundance and diversity of members belonging to the Firmicutes phylum. In the patient cohort, we find less diversity as well as increases in specific species often reported to be pro-inflammatory species and reduction in species frequently described as anti-inflammatory. Using a machine learning approach trained on the data obtained from 16S rRNA and inflammatory markers, individuals were classified correctly as ME/CFS with a cross-validation accuracy of 82.93 %.

Conclusions
Our results indicate dysbiosis of the gut microbiota in this disease and further suggest an increased incidence of microbial translocation, which may play a role in inflammatory symptoms in ME/CFS.

“Reduced diversity and altered composition of the gut microbiome in individuals with myalgic encephalomyelitis/chronic fatigue syndrome” by Ludovic Giloteaux, Julia K. Goodrich, William A. Walters, Susan M. Levine, Ruth E. Ley and Maureen R. Hanson in Microbiome. Published online June 23 2016 doi:10.1186/s40168-016-0171-4

Gut bacteria linked to chronic disease

Cleveland Clinic researchers have, for the first time, linked trimethylamine N-oxide (TMAO) — a gut metabolite formed during the digestion of egg-, red meat- or dairy-derived nutrients choline and carnitine — to chronic kidney disease.

TMAO has been linked to heart disease already, with blood levels shown to be a powerful tool for predicting future heart attacks, stroke and death. TMAO forms in the gut during digestion of choline and carnitine, nutrients that are abundant in animal products such as red meat and liver. Choline is also abundant in egg yolk and high-fat dairy products.

The research team was led by Stanley Hazen, M.D., Ph.D., Chair of the Department of Cellular & Molecular Medicine for the Lerner Research Institute and section head of Preventive Cardiology & Rehabilitation in the Miller Family Heart and Vascular Institute at Cleveland Clinic, and W.H. Wilson Tang, M.D., Department of Cardiovascular Medicine in the Miller Family Heart and Vascular Institute and Lerner Research Institute. The research will be published online on January 29th and in the January 30th print edition of Circulation Research.

According to the Centers for Disease Control and Prevention, more that 20 million Americans are estimated to have chronic kidney disease, many of whom are undiagnosed. It is caused by a gradual loss of kidney function over time. As the disease worsens, waste products can accumulate in the blood and can be fatal without interventions. It has long been known that patients with chronic kidney disease are at an increased risk for cardiovascular disease, but the exact mechanisms linking the two diseases are not known. This newly discovered TMAO link offers further insight into the relationship between cardiovascular disease and chronic kidney disease.

“It’s a triple whammy” said Dr Hazen. “Elevated plasma TMAO levels in subjects are linked to future cardiac risks, and in subjects with normal renal function, elevated levels predict long-term future risk for development of chronic kidney disease; animal model studies show that long-term exposure to higher levels of TMAO promotes renal functional impairment and atherosclerosis; and as the kidneys lose function, TMAO isn’t eliminated as easily, and levels further rise, increasing cardiovascular and kidney disease risks further.”

Drs. Hazen and Tang measured fasting TMAO levels in 521 patients with chronic kidney disease and in 3,166 subjects without chronic kidney disease, following all subjects over five years. They found that TMAO levels were higher in patients with chronic kidney disease, and elevated TMAO levels were associated with greater mortality risk in both subject groups. In animal models, the researchers also found that chronic dietary exposures to choline and TMAO were associated with development and progression of chronic kidney disease. Further studies are needed to determine if dietary interventions can delay disease progression of both chronic kidney disease and associated cardiovascular disease.

“Our studies raise the exciting prospects of nutritional interventions to help retard development and progression of chronic kidney disease. Regrettably, very little is known about diet and renal disease progression,” said Dr. Tang.

This research strongly implies the need to focus preventive efforts on dietary interventions and therapeutic targeting of gut microbiota-dependent TMAO pathways, potentially to halt development and progression of chronic kidney disease, as well as cardiovascular disease risks


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The above post is reprinted from materials provided by Cleveland Clinic.