Lactate biosensor could become…

… a simple test for CFS?

Credit: American Chemical Society. 

Saw this interesting article today. Since lactic acid and lactate is the prime substances that makes muscle feel exhausted and sour, may be this technique could become and easy way to test for CSF.

First human tests of new biosensor that warns when athletes are about to 'hit the wall'

Wednesday, 24 July 2013

A new biosensor, applied to the human skin like a temporary tattoo, can alert marathoners, competitive bikers and other "extreme" athletes that they're about to "bonk," or "hit the wall," scientists are reporting. The study, in ACS' journal Analytical Chemistry, describes the first human tests of the sensor, which also could help soldiers and others who engage in intense exercise — and their trainers — monitor stamina and fitness.

Joseph Wang and colleagues explain that the sensor monitors lactate, a form of lactic acid released in sweat. Lactate forms when the muscles need more energy than the body can supply from the "aerobic" respiration that suffices during mild exercise. The body shifts to "anaerobic" metabolism, producing lactic acid and lactate. That helps for a while, but lactate builds up in the body, causing extreme fatigue and the infamous "bonking out," where an athlete just cannot continue. Current methods of measuring lactate are cumbersome, require blood samples or do not give instant results. Wang's team sought to develop a better approach.

They describe the first human tests of a lactate sensor applied to the skin like a temporary tattoo that stays on and flexes with body movements. Tests on 10 human volunteers showed that the sensor accurately measured lactate levels in sweat during exercise.

"Such skin-worn metabolite biosensors could lead to useful insights into physical performance and overall physiological status, hence offering considerable promise for diverse sport, military, and biomedical applications," say the scientists.

Future research will further correlate sweat lactate levels with fitness, performance and blood lactate levels, Wang added.

Reference:

Electrochemical Tattoo Biosensors for Real-Time Noninvasive Lactate Monitoring in Human Perspiration

Wenzhao Jia, Amay J. Bandodkar, Gabriela Valdés-Ramírez, Joshua R. Windmiller, Zhanjun Yang, Julian Ramírez, Garrett Chan, and Joseph Wang 

Anal. Chem., 2013, 85 (14), pp 6553–6560, DOI: 10.1021/ac401573r

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ZenMaster

Here are some references...

...to the original work I talked about in my previous post. If anyone is interested I can send you a more complete list. Just send me an e-mail and ask for it!

ZenMaster

References related to energy metabolism in CFS:

• Assessment of cardiac metabolic disorders with positron emission tomography.

  Waldenstrom A, Langstrom B. Curr Opin Cardiol. 1991 Dec;6(6):965-71. Review. PMID: 10150067 [PubMed - indexed for MEDLINE]

• Human uterine smooth muscle exhibits a very low phosphocreatine/ATP ratio as assessed by in vitro and in vivo measurements.

  Steingrimsdottir T, Ericsson A, Franck A, Waldenstrom A, Ulmsten U, Ronquist G. Eur J Clin Invest. 1997 Sep;27(9):743-9. PMID: 9352245 [PubMed - indexed for MEDLINE]

• Ionophoric action on the cellular membrane as a pathophysiological mechanism in syndrome X: myth or reality?

  Waldenstrom A, Ronquist G. J Intern Med. 1995 Sep;238(3):187-9. No abstract available. PMID: 7673847 [PubMed - indexed for MEDLINE]

• Disturbed energy balance in skeletal muscle of patients with untreated primary hypertension.

  Ronquist G, Soussi B, Frithz G, Schersten T, Waldenstrom A. J Intern Med. 1995 Aug;238(2):167-74. PMID: 7629485 [PubMed - indexed for MEDLINE]

• Coxsackie B3 myocarditis induces a decrease in energy charge and accumulation of hyaluronan in the mouse heart.

  Waldenstrom A, Fohlman J, Ilback NG, Ronquist G, Hallgren R, Gerdin B. Eur J Clin Invest. 1993 May;23(5):277-82. PMID: 8394817 [PubMed - indexed for MEDLINE]

• Phosphocreatine turnover and pH balance in forearm muscle of patients wit syndrome X.

  Soussi B, Schersten T, Waldenstrom A, Ronquist G. Lancet. 1993 Mar 27;341(8848):829-30. No abstract available. PMID: 8096030 [PubMed - indexed for MEDLINE]

• Angina pectoris patients with normal coronary angiograms but abnormal thallium perfusion scan exhibit low myocardial and skeletal muscle energy charge.

  Waldenstrom A, Ronquist G, Lagerqvist B. J Intern Med. 1992 Apr;231(4):327-31. PMID: 1588255 [PubMed - indexed for MEDLINE]

• Low energy charge in human uterine muscle.

  Wedenberg K, Ronquist G, Waldenstrom A, Ulmsten U. Biochim Biophys Acta. 1990 Jan 29;1033(1):31-4. PMID: 2137351 [PubMed - indexed for MEDLINE]

Now comes the big news...

...even though it is almost twenty years old!

In the late 1980-ies and early 1990, my cardiologist together with a biochemist at the hospital designed and performed a series of experimental investigations that really turned out to give some new results on what is wrong when you have CFS.

In short, something is wrong with the energy consumption, or as we cell biologists say the ATP metabolism. ATP is the prime energy molecule in cells, and most of it is produced in the mitochondria of cells. It was not that there is too little ATP, on the contrary the synthesis in my heart or skeletal muscle cells were 3-5 times the normal when tested on biopsies. Still, after only a few minutes work, the ATP levels could drop to only 10 or 20 percent of the normal values, while in normal people it only decrease 10 or 15 percent in total, during the same conditions. Furthermore, it took more than an hour of rest to regain the ATP levels I should have, while the control persons got their ATP back within a few minutes.

Another observation from these experiments was that the acidity, or pH value, inside the muscle cells dropped dramatically, from the normal 7.2 down to 6.0. This was so extreme that no one had seen before, and was believed the cells shouldn’t survive, but obviously I did – well my muscle cells was live and had no ultrastructural damages seen in many other conditions. When this result was repeated at several occasions, and with different techniques, we had to believe they were correct. The low pH was also related to production and release of large amount of lactic acid in the blood.

All these experimental data fits so well with the clinical picture! I can move around, but slowly in order to not ware out totally. However, when exercised in some way – like walking for a while slowly – it can take more than a day, even two days before I am back to my “normal” level of strength. And I still feel – always – as I have been running a marathon in my legs. That is a lot of lactate all the time, giving me muscle ache.

Later, I will try to tell more about the specific tests that were done – give more technical details – because I think this is a very important finding they did, not only on me but on a small group of people with CFS here where I live. However, it was never noticed at other research places, even though most of these results were published in scientific journals. One explanation could have been it was rather difficult and complex experiments to perform, but I really don’t know why.

Well, so much for my story today. No treatment came out of this, and I still suffering the same way, untreated. And the reason for this metabolic disturbance, the original cause, is still of course obscured.

But if you want, go ask your doctor about these things! Maybe there are someone that will be able to take up this again, and come a little further!

ZenMaster