Reprinted with the kind pernission of Simmaron Research
Maureen Hanson has been making waves. An ace molecular plant biologist prior to entering the chronic fatigue syndrome (ME/CFS) field, Hanson has worked on mitochondrial and gene studies in plants dating back decades. Now, with her son ill from ME/CFS, she’s turned her talents to this field, and has made a difference in a hurry.
A trusted researcher, Hanson scored one of the few XMRV grants and in a short period of time has produced studies on the gut, mitochondrial DNA, exercise, and metabolomics in ME/CFS. Last year, Hanson, created one the few chronic fatigue syndrome (ME/CFS) research centers in the U.S. (the Cornell Center for Ennervating NeuroImmune Disease, ) and this year she and her colleagues received one of the three NIH ME/CFS Research Center grants. She’s also a member of the Simmaron Research Foundation’s Scientific Advisory Board.
Last year Hanson was awarded a smaller NIH grant (R21) to do preliminary work assessing the energy production in ME/CFS patients’ immune cells using the Seahorse XF Analyzer. In this blog we take a closer look at the work underway.
A Breakthrough Technology
It’s safe to say that the Seahorse machine is changing how researchers do research. In the mid-2000s the Seahorse folks introduced something new to the medical world called “extracellular flux (XF)” technology. A monolayer of cells is placed in a very small, 10 ml sensor chamber and then stimulated. Every few seconds a sensor placed 200 microns above the cell monolayer takes a measurement. Where past techniques required hours to assess oxygen metabolism, the Seahorse can do it in minutes.
This technology allows researchers to determine the energy consumption of cells by analyzing changes in oxygen and acid levels occurring in the media outside of them. The amount of oxygen present indicates how much energy is being produced through glycolysis and by the mitochondria.
The ability to place energy stimulating or inhibiting or other drugs in the sensor chamber brings the possibilities of the Seahorse machine to an entirely new level. If the inability to produce energy turns out to be a key factor in ME/CFS, the Seahorse machine’s ability to test how drugs and other substances effect the energy production of cells could be a big boon indeed
Agilent, the company that produces the Seahorse machine, reports the machine has been used in over 250 studies. HIV researchers, for instance, recently used the machine to determine the effectiveness of the immune response in HIV patients. It turns out that in order to meet a threat, many of our immune cells undergo a huge metabolic shift as they get transformed from a resting to an active state. That shift coincides with large increases in glycolysis in particular.
A similar approach is being used in chronic fatigue syndrome (ME/CFS). Tomas’ recent Seahorse study suggested that ME/CFS patients’ immune cells (PBMC’s (T, B and NK cells, monocytes))are having severe problems producing energy. Tomas’ study opened up an important possibility but it was limited by its inability to determine which cells were having problems.
Hanson is taking the next step in assessing immune functioning in ME/CFS with her R21 NIH grant. That grant gave her the funds to assess the energy production of individual immune cells separately (T, B and NK cells). (Isabel Barao is also examining energy production in NK cells).
Each of these cell types has been potentially implicated in ME/CFS. The T-cell problems Derya Unutmaz of Jackson Labs saw are what attracted him to ME/CFS, and Mark Davis of Stanford recently found signs of unusual clonal expansion in ME/CFS patients’ T-cells. The success some ME/CFS patients have with Rituximab suggests B-cell issues are present, and the problems ME/CFS patients’ natural killer cells have with killing have been known for decades.
T-cells are a particularly good subject because springing into action to kill other cells or to produce clones of themselves to fight invaders requires enormous amounts of energy. If energy production is flawed in ME/CFS, it’s probably going to show up in patients’ immune cells.
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Metabolomic studies suggest glycolysis might be inhibited in ME/CFS, but at the OMF’s Stanford Symposium Hanson stated that she hasn’t found impaired glycolysis. When glucose was given to the immune cells to stimulate their glycolytic processes, the cells were able to use it, but their respiratory capacity (oxidative phosphorylation) was blunted.
In another study, which the SMCI helped to fund, Hanson’s Metabolon metabolomics study found lower glucose levels (a surprise) as well as differences in fat and lipid metabolism (i.e. energy production), and in the sphingolipids that play a big role in Naviaux’s findings.
Hanson noted that low glucose levels are not a good sign, either. Low glucose levels have been associated with increased cortisol responses (possibly leading to exhaustion) and inflammation. Plus they may be able to mess with a person’s endurance.
The last sport anyone with ME/CFS is going to engage in is an endurance race. That might make sense given that athletes with lower glucose levels tend to do worse in endurance sports. Overall Hanson’s metabolite findings suggest increased inflammation and reduced recovery from metabolic stress are part and parcel of ME/CFS. Metabolic stress, of course, is exactly what she’s measuring in her Seahorse study.
Hanson’s finding of normal glycolysis in ME/CFS patients’ T-cells mirrors the findings of Tomas’ recent Seahorse study. However, Hanson’s early findings are suggesting that, at least in the immune cells, the mitochondria are the issue.
Hanson has found that ME/CFS patients’ T-cells use less of their “respiratory capacity” when provoked than do healthy controls’ cells. If I’m reading this right, the capacity to produce energy is there, but it’s not being used. The next step is to determine if the T-cells, when they become activated, can produce enough energy to be effective. If Dr. Hanson finds they’re not up to the task of producing adequate energy, she said, “they may also be unable to effectively respond to an immune challenge.”
Lethargic T-cells could have major implications for the immune system, as T-cells are important in just about every immune system activity. At least four different kinds of T-cells exist: T-helper cells activate B and NK cells, T-killer cells destroy virally infected and cancerous cells, T-memory cells alert the immune system to danger, and T-regulatory cells help keep the immune system humming. Small studies suggest that cytotoxic or killer T-cells have the same problems with killing infected cells that NK cells do.
Whether or not something in ME/CFS patients’ blood is essentially putting their cells to sleep is one of the more fascinating questions facing this field. Several researchers including Ron Davis of the Open Medicine Foundation and Fluge and Mella in Norway believe something in the blood is doing just that. Energy production issues in ME/CFS patients’ cells that have been isolated from the blood suggest that something may be wrong with the cells themselves. It’s possible, therefore, that problems may lie in both the blood and the cells.
Since the Seahorse machine allows researchers to insert different substances in the medium the cells are bathed in, I asked Dr. Hanson if she could use the machine to determine the effects ME/CFS patients’ blood may be having on their immune cells.
Dr. Hanson replied that the Seahorse machine could determine if something in ME/CFS patients’ serum affects mitochondrial function in immune cells from healthy people, but the Seahorse technology would not be able to tease out what factors in the serum are responsible.
The Seahorse requires large samples of difficult to obtain immune cells. T-cells are relatively easy to obtain; B and NK cells – not so much. Getting Maureen Hanson the resources she needs to do her work is where the Simmaron Research Foundation comes in: it’s supplying the cells she needs to do her work. Dr. Hanson stated that, “We are grateful to Simmaron Research for supporting the collection of additional samples from which individual cell types— such as B and NK cells—can be purified for analysis of glycolysis and oxidative phosphorylation”.
Next up, Dr Hanson will analyze the cellular energetics of those NK and B cells. Despite the Rituximab failure, B-cells are still of great interest in chronic fatigue syndrome (ME/CFS). It’s still possible, for instance, that the drug works for a significant subset of patients. Plus B-cells are heavily involved in autoimmunity. Dr. Light has proposed that energy depleted B-cells may increase the risk of an autoimmune process beginning.
The desire to examine NK cells is obvious. Reduced NK cell cytotoxicity is a hallmark of ME/CFS, and reduced cytotoxicity of T-cells appears to be present as well. Could that poor killing power be caused by the most basic of all problems – the inability to generate enough energy? Given the high energy requirements of activated immune cells, that’s a distinct possibility. Dr. Hanson’s work will take us closer than any other yet to answering that most fundamental of all questions.
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