Gene expression alterations at baseline and following moderate exercise

[Bob]

Gene expression alterations at baseline and following moderate exercise in patients with Chronic Fatigue Syndrome, and Fibromyalgia Syndrome.

Light AR, Bateman L, Jo D, Hughen RW, Vanhaitsma TA, White AT, Light KC

J Intern Med. 2011 May 26. doi: 10.1111/j.1365-2796.2011.02405.x. [Epub ahead of print]

26 May 2011

http://www.ncbi.nlm.nih.gov/pubmed/21615807




(Department of Anesthesiology, University of Utah, Salt Lake City, UT The Brain Institute, University of Utah, Salt Lake City, UT Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT Department of Exercise and Sprt Science, University of Utah, Salt Lake City, UT.)

 

[redo]

Very good find bob.

 

[Dolphin]

One important typo and two less important typos (I think)

One important typo and two less important typos (I think)

Dear Drs Light,

Thank you for your latest paper, "Gene expression alterations at baseline and following moderate exercise in patients with Chronic Fatigue Syndrome, and Fibromyalgia Syndrome" which I think is excellent.

I thought I would draw attention to 3 (possible?) typos, one of which I think is quite important.

In figure 4, [STRIKE]it has as its title "CFS+FMS grouped by clinical severity" with another small graph saying, "CFS-FMS patients" - the latter being somewhat similar to controls.

What I believe these should say are "<alpha-sign>-2a" increase and "<alpha-sign>-2a" decrease respectively.
I think that is quite an important error to try to fix as the big difference in this study wasn't the difference between "CFS+FMS" and "CFS-FMS" patients.[/STRIKE]
ETA: After a little discussion, he agrees the heading should be "<alpha-sign>-2a" increase. The small one was supposed to be simply the legend not a separate score.

The other two typos I think are less important:
- "The minor subgroup, the ?-2A decrease group (n=14), had 1 patient with severity 1 (7%), 4 patients with severity 2 (29%), 6 patients with severity 3 (43%) and 2 patients with severity 4 (14%). One patient had severity 1."
I think that the last sentence should say "One patient had severity >4" or "One patient was less severe than 4" (or perhaps that should be "One patient had severity <1") - I think it is more likely to be less severe than 4 to match the previous section which had, "Two patients were not included for this analysis because they were less severe than 4."

ETA: he agrees (I presume he means "One patient had severity >4")

- "Ratings of Perceived Exertion (RPE) were obtained on a scale of 1-10 every 45 min; heart rate was recorded every minute, and blood pressure was measured at baseline, every 10 min during exercise, and upon completion of the exercise." I presume that "every 45 minutes" is incorrect considering that the exercise test only lasted 25 minutes - I'm guessing but cannot be sure that it was supposed to be "every 45 seconds".

ETA: He says this should be "Ratings of Perceived Exertion (RPE) were obtained on a scale of 1-10 every 4-5 mins"

Thanking you for your time and your interest,

 

[Dolphin]

I'd recommend anyone who can gets a chance reads this paper, as it's very good. Also, the graphs again are very impressive.

Information on cohort:

The sample for the present report included 48 CFS patients (33 females) [19 (15 females) of these
are the same patients as in our previous publication [8]], 49 Control subjects (29 females) [16 (11
females) are the same Controls as in our previous report], and 18 FM only subjects (15 females).
This ratio of more females than males is typical in CFS and FM research, and is also consistent with
observations from large scale incidence and prevalence studies including the Wichita sample [10].
The patients reflected the local population with 94% being Caucasian, 6% being minority; thus our
findings may not apply to minorities with CFS or FM. All CFS patients met the CDC criteria for CFS
[1], and 46 (96%) met the Canadian Criteria for ME/CFS as well [2] . Prior screening by an
experienced physician (LB) ruled out all other known causes for persistent or relapsing fatigue in
these CFS patients. All patients were also screened for FM using the strict ACR research criteria,
which includes presence of widespread pain for at least 6 months, and pain reported at 11 or more of
18 sites during tender point examination [3]. Thirty three of the 48 CFS patients (69%) also met ACR
criteria for FM, similar to the high co morbidity of these disorders previously reported [11-13].
Eighteen patients met criteria for FM, but did not meet criteria for CFS (principally due to fatigue
causing less compromise in normal daily activities), and were classified as FM-only patients (FM).

Interesting point about the exercise test to use (although I'm not sure if it's that clear cut):

We elected to use a sustained moderate exercise rather than a maximal exercise test
(which typically last only 5-9 min in CFS patients) because of closer similarity to the natural exercise
experiences reported to exacerbate CFS symptoms in patients daily lives. Our 25 min sub-maximal
exercise task did elicit consistent worsening of fatigue and pain symptoms from 8-48 hours postexercise
(see Fig. 1). In contrast, after a briefer maximal exercise task, reports of worsening CFS
symptoms were inconsistent or absent until 5 days after the challenge [14], a pattern not typically
observed in real life. Maximal exercise protocols have demonstrated few differences in
cardiorespiratory and perceptual responses; RPE is an exception being consistently higher in CFS
patients than controls [15]. However, it is notable that responses to sub-maximal exercise including
VO2 do predict peak exercise performance in CFS patients [16].

14. Yoshiuchi, K., D.B. Cook, K. Ohashi, H. Kumano, T. Kuboki, Y. Yamamoto and B.H. Natelson.
A real-time assessment of the effect of exercise in chronic fatigue syndrome. Physiol Behav.
2007; 92: 963-968.
15. Cook, D.B., P.R. Nagelkirk, A. Poluri, J. Mores and B.H. Natelson. The influence of aerobic
fitness and fibromyalgia on cardiorespiratory and perceptual responses to exercise in patients
with chronic fatigue syndrome. Arthritis Rheum. 2006; 54: 3351-3362.
16. Nijs, J., S. Demol and K. Wallman. Can submaximal exercise variables predict peak exercise
performance in women with chronic fatigue syndrome? Arch.Med Res. 2007; 38: 350-353.

Some basic confounders were ruled out as being important to differences:

To examine whether Group differences were related to differences in age, gender, or body mass
index (BMI), we performed one way ANOVAs with each of these included in the model as covariates.
In no instance did age, gender, or BMI impact the significance of group differences.

Results:

Figure 1 depicts mean ratings of mental fatigue, physical fatigue and pain on our 0-100 scale in the
various groups before, during and after the exercise task. In control subjects, exercise did not
increase ratings of mental fatigue or pain at any time point; and physical fatigue was increased only at
mid-exercise and not at any post-exercise time. In sharp contrast, exercise caused significant
increases in all fatigue and pain measures at all time points during and after exercise in CFS only and
in CFS+FM patients. Patients with FM reported increases in pain and physical fatigue at all time
points, and increases in mental fatigue at all time points except during and immediately after exercise.
As can be seen in Figure 1, the two CFS subgroups distinguished by post-exercise adrenergic ?-2A
increases vs. decreases (described in detail below) did not differ from each other in ratings of pain or
fatigue. Not surprisingly (since these patients were defined by having less pain than FM or CFS+FM
patients), patients with CFS only had lower pain scores during and immediately after exercise than
the CFS+FM or FM groups. Thus, this very moderate level of exercise for 25 min caused postexertional
malaise lasting 48 hours in all CFS and FM patient groups, but not controls.

This is interesting. Generally I think "CFS trumps FMS" i.e. if you have CFS and FMS, follow the CFS advice (for exercise anyway) - this suggests this could be a fair assessment:

CFS patients compared with CFS patients who also have co-morbid FM.
Initially, we divided the CFS patients into those that had CFS, but did not meet criteria for FM, and
those CFS patients who also met criteria for FM, i.e., they had both CFS and FM (CFS+FM). None of
the descriptive variables in Table 1 were significantly different between these groups. Likewise,
comparison of these two groups showed very similar gene expression both before and after exercise.
Only post-exercise ASIC3 AUC was greater in the CFS+FM vs. the CFS only patients (P < .046). For
this reason, in all of the following analyses, CFS only and CFS+FM patients are grouped together.

Baseline gene expression doesn't tell us much about CFS/help us distinguish with controls (for these genes):

CFS patients showed no baseline changes in gene expression from Controls; FM patients showed
baseline increases in 3 genes.

Correlations
Table 3 shows the correlations between the behavioral scores for fatigue and pain and AUC gene
expression measures, as well as inter-correlations between the various genes. These indicate strong
positive relationships between post exercise pain and fatigue and increases in P2X4, TRPV1, ?-2A,
?-2, and IL10. Relationships between the behavioral measures were weaker for the ASIC3, P2X5,
and the other cytokine genes measured.

Table 3 = Correlations of Post-exercise AUC Gene Expression Measures with Post-exercise AUC Fatigue and Pain
and with Each Other (All ?-2A increase CFS patients and controls included in this analysis)

The discussion section I think is very good overall - too many points to post I think.

 

[mellster]

Nice find! That is consistent with my observations as well that - being a mild(er) CFS/FM case - continued moderate-to-high aerobic exercise beyond a certain time threshold (~ 30 mins depending on conditioning) without enough time to recuperate will increase the likelyhood for PEM in the aftermath. Obviously the time and intensity thresholds are fluid and dependent on the individual but I bet that the trend they found will be validated by other studies. It might be somehow related to faster depletion of aerobic fiber for CFS patients due to lack of oxygenation, mehtylation and malabsorption And I still think like redo that a lot of the patients could be bettered by fixing the gut cause I have the hunch that nutrient malabsorption together with viral/adrenal fatigue causes that consistent state of maloxygenation. The genetic expressions have to play a part in this.

 

[Esther12]

I've only read the abstract, and doubt I'd understand the full thing properly, but it would have been nice to get sedentary controls, to make sure these differences aren't just related to lower fitness/activity levels. Could that be a plausible or partial explanation at this point?

 

[Dolphin]

(has this post long lines and short lines?)

I've only read the abstract, and doubt I'd understand the full thing properly,

Abstracts I find can be harder to read often - they're very dense and things aren't explained. For what it's worth, I was able to understand this paper even though my knowledge of exercise physiology and biochemistry is minimal - I still couldn't tell you exactly what each individual chemical does exactly but one doesn't need to know.

but it would have been nice to get sedentary controls, to make sure these differences aren't just related to lower fitness/activity levels. Could that be a plausible or partial explanation at this point?

They do say:

We have shown in a recently submitted manuscript that these gene markers are not similarly
increased in patients with MS who exhibit unexplained increases in fatigue (White, A.T., Light A.R.,
Hughen R.W., VanHaitsma T.A., and Light K.C. Differences in metabolite-detecting, adrenergic, and
immune gene expression following moderate exercise in multiple sclerosis, chronic fatigue syndrome,
and healthy controls, submitted). We also have preliminary data indicating that these genes are not
increased before or after exercise in patients with unexplained fatigue who have advanced prostate
cancer.

Also they tested if Ratings of Perceived Exertion could explain the differences:

To ensure that these findings were not solely due to differences in exertion, we performed a
secondary analysis after reducing our sample to the CFS and Control subjects who were matched on
Ratings of Perceived Exertion (RPE). This analysis confirmed our central findings. This comparison
examined 15 controls with the highest RPE (mean 3.89) matched with 27 patients with overlapping
RPEs (mean 3.87). Even though this reduced our sample size and statistical power substantially, 6
of the 7 genes AUCs were still significantly greater in CFS patients than controls [P2X4 (p<.05),
TRPV1 (P<.02), ?-2A (P<.03), ?-2 (P<.03), COMT (P<.04), and IL10 (P< .01)]. The only gene not
reliably different was P2X5 (P=.12).

and

Contrary to expectations, FM patients who did not meet criteria for CFS, that is, without chronically
diminished function specifically linked to fatigue, did show evidence of post-exertional malaise
reflected as increases in self-reported fatigue and pain measures for 48 hours after moderate
exercise. However, the FM patients did not show reliable post-exercise increases in mRNA for any
gene under study. Although their average work rate was higher than the CFS patients, FM patients
had lower average increase in heart rate than CFS patients. This differential in work rate and heart
rate increase may be due to less de-conditioning on average in the FM group vs. the CFS group.
However, it is unlikely that this explains the post-exercise gene expression differences between the
CFS and FM-only patients because a post hoc analysis using only those CFS patients whose work
rates were matched to those of the FM patients indicated that these CFS patients still showed greater
increases in mRNA than controls (P < .05), unlike the lack of increases observed in FM patients.

 

[mellster]

Hi Esther,

I know one person is not statistically significant, but I scored high (for my age group) on the CV fitness treadmill test, which is basically 10-15 minutes high impact increasing incline and speed on the treadmill. I was feeling unwell and fatigued before taking the test and had no PEM whatsoever afterwards. I am also fairly active when doing well so I doubt that I am deconditioned by traditional understanding. I see this as 80% of a recovery and depletion problem and think that the genes might play a role in this as I have always had minor recovery problems all my life (but far form the extent since CFS onset). I think that people can be fairly athletic or strong but weakness might show mostly during aerobic endurance and moreso during the recovery period. Add lack of sleep, stress and gut problems plus viral stressors to the mix and you have the perfect setup for a crash. That's why I think graded exercise is wrong without specific modification, i.e. only increase time and intensity when you feel good and rested and decrease/modify as soon as you begin feeling depleted or having other stressors in your life that could aid to a crash. Since the common nature of doctors is not to stay with you throughout all the stages of health in your life and not knowing about possible current co-factors, I think scientists and doctors should be left with finding the best treatment options - drugs and supplements - for the cause(s) of CFS while you have to become either your own personal trainer/nutritionalist or find one to spend that important journey to betterment in your life with you (money is obviously a big issue), but as much as I would like to wake up and pop a newly discovered pill and have it all gone I think it will require at least a 2-pronged approach and take time and determination (and money).

 

[Esther12]

We have shown in a recently submitted manuscript that these gene markers are not similarly
increased in patients with MS who exhibit unexplained increases in fatigue (White, A.T., Light A.R.,
Hughen R.W., VanHaitsma T.A., and Light K.C. Differences in metabolite-detecting, adrenergic, and
immune gene expression following moderate exercise in multiple sclerosis, chronic fatigue syndrome,
and healthy controls, submitted). We also have preliminary data indicating that these genes are not
increased before or after exercise in patients with unexplained fatigue who have advanced prostate
cancer.

Oh excellent. Thanks Dolphin.

lol - it seems like an obvious point, but I'm so used to CFS papers with obvious flaws! I got a genuine shiver of excitement upon reading how well they'd dealt with that concern. Maybe I will try to read the whole thing - it would be nice to read a paper that might be helpful for us, rather than only reading the ones by people I least respect.

 

[Esther12]

Hi Esther,

I know one person is not statistically significant, but I scored high (for my age group) on the CV fitness treadmill test, which is basically 10-15 minutes high impact increasing incline and speed on the treadmill. I was feeling unwell and fatigued before taking the test and had no PEM whatsoever afterwards. I am also fairly active when doing well so I doubt that I am deconditioned by traditional understanding. I see this as 80% of a recovery and depletion problem and think that the genes might play a role in this as I have always had minor recovery problems all my life (but far form the extent since CFS onset). I think that people can be fairly athletic or strong but weakness might show mostly during aerobic endurance and moreso during the recovery period. Add lack of sleep, stress and gut problems plus viral stressors to the mix and you have the perfect setup for a crash. That's why I think graded exercise is wrong without specific modification, i.e. only increase time and intensity when you feel good and rested and decrease/modify as soon as you begin feeling depleted or having other stressors in your life that could aid to a crash. Since the common nature of doctors is not to stay with you throughout all the stages of health in your life and not knowing about possible current co-factors, I think scientists and doctors should be left with finding the best treatment options - drugs and supplements - for the cause(s) of CFS while you have to become either your own personal trainer/nutritionalist or find one to spend that important journey to betterment in your life with you (money is obviously a big issue), but as much as I would like to wake up and pop a newly discovered pill and have it all gone I think it will require at least a 2-pronged approach and take time and determination (and money).

Ta mellster. It's a pain. Magic pill sounds more fun imo.

 

[Dolphin]

This graph from a previous paper might motivate some people to consider reading it (I'm not saying it's essential):

 

[mellster]

Thanks Dolphin - very revealing! A must read slide for every doc out there learning about CFS/FM.

 

[Bob]

Thanks Dolphin.

I haven't read it all yet, but it looks like a very helpful and interesting study.
The gene expression changes due to exertion seem to be very helpful for us to demonstrate that post-exertional-malaise is a real and physical feature of ME.

 

[oceanblue]

Fascinating indeed. That MS data might just persuade me to read 44 page of the full article posted in the library, when I have time...

 

[ukxmrv]

Remember that the pro-CBT brigade claim that they can change (i.e. fix ) gene expression (From the UK Gibson Inquiry on ME, by Lord Turnberg at one meeting)

 

[Dolphin]

Remember that the pro-CBT brigade claim that they can change (i.e. fix ) gene expression (From the UK Gibson Inquiry on ME, by Lord Turnberg at one meeting)

Not sure the relevance of this? Should we run away from it because they suggest they can change it (without evidence)? There is a huge amount of different "gene expression" that could be tested so even if they might change one thing, they might not change another such as the abnormalities found here.

 

[ukxmrv]

Thanks Dolphin,

It would probably cost us UK5 million to find out anyway (the evidence).

Certainly should not run away from it. Just be aware of the propoganda that will be used to try and discredit these findings.

 

[Dolphin]

Asked in the duplicate thread which will hopefully get locked:

Thanks for the link. Do you know what they are referring to when they say "published biomarker criteria"?

Previously, we suggested that mRNA expression of some of the genes measured here might be
useful as objective, blood based biomarkers for CFS [9]. For the major subgroup reported here (the
?-2A increase patients) a combination of PX4, ?-2A, B-2, and IL10 at all time points after moderate
exercise, sensitivity can be as great as 0.93 with a specificity of 0.77, or specificity can be as great as
0.91 with a sensitivity of 0.77. The AUC of the Receiver Operating Curve was 0.91 with a 95%
confidence interval of 0.83- 0.98. In either case, accuracy was 0.80. This would be considered a
Very Good to Excellent diagnostic tool [51]. Reliable diagnostic values for the ?-2A decreasing
patients could not be accurately computed because of small sample size (n=14).

 

[oceanblue]

Promising, but not there yet

I really like what the authors are trying to do here - look at how gene expression in CFS patients differes from controls after moderate exercise - but I think the results are compromised by the fact that the exercise was not always moderate for CFS patients. Here's what they tried to do:

We elected to use a sustained moderate exercise rather than a maximal exercise test (which typically last only 5-9 min in CFS patients) because of closer similarity to the natural exercise experiences reported to exacerbate CFS symptoms in patients daily lives
...
We attempted to adjust for fitness level mismatches by exercising all patients and controls at the same relative exercise intensity, to 70% of age predicted, maximal heart rate.

The problem with this approach is that for the most severely affected patients (bedbound/housebound) 70% of max heart rate for 25 mins is way, way more than moderate exercise and is vastly more than "natural exercise experiences reported to exacerbate CFS symptoms in patients daily lives". I would be in the second most severe category, 'could live alone with occasional help' and know from trying in the past that I could only manage 70% of max heart rate for a few minutes - my problems are caused by activity way below this.

The mean score for self-rated exertion for the control group was 3.1, which is just right as a score of 3 equates to moderate exertion. For the CFS group the mean was 5.0 ('hard' exertion) but would have been substantially higher than this for some patients. [from other data given, the exertion for the 21 most exhausted patients can be calculated as 6.5, equivalent to 'very hard' exertion]

This matters, because the genes chosen for study have increased expression for strenous exercise in healthy controls:

Initial experiments with normal subjects indicated that mRNA for [genes in this 2011 study] was upregulated at 8 and 24 hours after strenuous exercise. (from 2009 pilot study)

Worryingly, figure 3 shows that the biggest increases by far for gene expression are in the two most severely affected groups whose exercise level is likely to be far above moderate. It could be argued this is exactly as expected for individuals exercising very hard, not evidence for a specific disease process.

Now, as Dolphin noted, the authors do address this point by an analysis that only looked at patients and controls with similar exertion levels:

This comparison examined 15 controls with the highest RPE (mean 3.89) matched with 27 patients with overlapping RPEs (mean 3.87). Even though this reduced our sample size and statistical power substantially, 6 of the 7 genes AUCs were still significantly greater in CFS patients than controls [P2X4 (p<.05), TRPV1 (P<.02), -2A (P<.03), -2 (P<.03), COMT (P<.04), and IL10 (P< .01)]. The only gene not reliably different was P2X5 (P=.12)

This is an important finding. However, the statistical significance is much less impressive than for the full study (no doubt due to losing the patients with the biggest differences, as well as the inevitably smaller sample size) and the sample size is small. We don't know if the alpha-2a subgroup exists in this smaller sample.

What this leaves us with is effectively a pilot-study type result (15 controls/27 patients vs 49/48 in the full study), rather than a confirmatory result. It's still very interesting, but it's not nearly as convincing.

Well, that's my take. I'm happy for anyone to point out flaws in my logic. Otherwise, to be convinced I'd like to see rersults for a much larger study and ensure that exertion/exercise levels are appropriate for the level of severity experienced by each CFS patient.

 

[Dolphin]

Link to CAA summary

The CAA, who part-funded it, have done a detailed summary. It can be read at: http://www.research1st.com/2011/06/02/exercise-challenge-reveals-potential-cfs-biomarkers/ . I'd recommend reading it on the site rather than somewhere elsewhere (in plain text) as they have included some graphs.