A growing body of research indicates that Chronic Fatigue Syndrome (CFS) can come in two forms. One of them is caused by a viral infection, while the other is due to a disturbance in the production of a certain protein.
Despite the almost confirmed no relationship between XMRV (xenotropic murine leukemia virus-related virus) and pMLV (polytropic murine leukemia virus) viruses, suspected of causing Chronic Fatigue Syndrome (CSF), a team of scientists from the University of South Florida is conducting research over the viral basis of this disease. The group found a link between a long-known virus and CSF. It is the human herpes virus type 6 (HHV-6) that may be responsible for the acute forms of CSF.
Hidden and functional herpesvirus
Over 95 percent the 3-year-old population is infected with HHV-6, but an efficient immune system copes well with the virus and remains inactive. HHV-6 causes fever and erythema or rubella in early childhood and is spread through saliva. In the case of a defective immune system, it can cause neurological disorders, encephalitis and pneumonia.
The good news from our research is that antiviral medications reduce the most unbearable symptoms of Syndrome, felt by a large proportion of patients, such as pain and chronic fatigue. You can count on the fact that 15-20 thousand. US patients with CSF will benefit from antiviral therapy based on the results of our research, Prof. Medveczky.
The relationship between CSF and HHV-6 is quite complex. After infection, 9 known human herpes viruses remain latent (hidden), but under favorable circumstances, such as a decline in the immune system or an aging body, they can cause disease. The team of prof. Medveczky stated that HHV-6 is an exception – although hidden, its DNA integrates into the terminal part of human chromosomes called telomeres. Such an integrated virus can spread from parent to child as. Other herpesviruses turn into spore forms in the nuclei of infected cells, do not integrate into chromosomes and cannot be passed on to the next generation.
As a result of such transmission, about 0,8 percent. UK and US populations are carriers of HHV-6 and have obtained this virus through inheritance. This indicator is similar for the entire European Union. A greater percentage of infected may occur in East Germany and Central European countries, and a smaller percentage in Scandinavia. Theoretically, this form of the virus does not harm people. However, it acts negatively in another way – it lowers their resistance to re-infection with another HHV-6 strain with which they may be dealing. In such re-infected, the symptoms of the Chronic Fatigue Syndrome are observed.
CSF or IHS?
In the group of patients with acute neurological symptoms of the Syndrome, there are 2 percent. people with proven CIHHV-6 (HHV-6 virus integrated with DNA), i.e. by 100 percent. more than the average in the healthy population. According to the authors of the research, this means that we are dealing with a form of CSF, which should be called Inherited Human Herpesvirus 6 Syndrome or IHS (Inherited Human Herpesvirus 6 Syndrome).
The team of prof. Medveczky carefully examined patients with CIHHV-6 and acute symptoms of Chronic Fatigue Syndrome. The researchers noted that infection with another HHV-6 strain caused the first integrated virus to reactivate. After six weeks of antiviral therapy, the health and quality of life of patients with Chronic Fatigue Syndrome improved. Muscle pains decreased, sleep quality improved significantly, insomnia disappeared completely, memory and concentration improved.
Of course, as scientists from the USA claim, research on IHS is only the beginning of isolating this disease from the conceptual bag of Chronic Fatigue Syndrome. It will be necessary to examine the disorders of the immune system associated with the constant occurrence of HHV-6 in patients and the relationship between this disease entity and CSF.
CSF or no ASIC3
Meanwhile, a team of scientists from Iowa led by prof. Kathleen Sluka decided to investigate Chronic Fatigue Syndrome from the side of the symptoms, hoping that this way it would be possible to discover a therapy and determine the cause of the condition. The first studies found that the chronic pain associated with CSF could be relieved, thereby significantly reducing the symptoms of the disease.
Chronic muscle pain occurs in over 94% of people. people diagnosed with Chronic Fatigue Syndrome and is one of the ailments that make everyday life difficult for patients. Almost all women diagnosed with CSF complain about them. These pains usually spread to the muscles of the back and legs
In order to check whether it is possible to eliminate these ailments and to what extent their elimination will facilitate the treatment of the Chronic Fatigue Syndrome, the team of prof. Sluki started his research on a mouse model. Male and female mice with or without ASIC3 – an acid-activated ion channel protein – began to undergo a regimen of strenuous exercise to induce fatigue back pain. ASIC3 is a protein that directly participates in the action of the skeletal muscles of the back, a significant reduction in its presence is observed in people with CSF.
Exercises took place in three daily turns of one hour each and had a different difficulty system for each group of mice. After the exercise, the degree of muscle strength loss of each mouse caused by such training was measured.
Males were found to be less tired than females, but ASIC3-deficient males showed a degree of fatigue comparable to ASIC3 females and greater than other males. However, when ASIC3 females were given low doses of testosterone, their muscles were as resistant to fatigue as ASIC3 males. Testosterone had no effect on ASIC3-deficient females. As prof. Sluka, the research clearly shows that ASIC3 protein and testosterone significantly reduce the level of fatigue in the skeletal muscles of the back. This would explain why all women with CSF have pain, but not all men with CSF. Currently, according to scientists, it is necessary to find out how the value of ASIC3 decreases in people with Chronic Fatigue Syndrome, what are the reasons for the decrease in the level of this protein and how it changes over time. There also remains the development of an effective testosterone-based therapy; possibly separate for the doses for men and women.
Arrhythmia Syndrome Indicator
Meanwhile, a team of Australian scientists found that sudden arrhythmia and a reduction in the number of heartbeats may be a very good indicator of the upcoming cognitive disorders, e.g. concentration, characteristic of the Chronic Fatigue Syndrome. It also signifies the near onset or imminent attack of this disease.
“When examining autonomic functions in CSF, we found beyond any doubt a decline in the integrity of the stress response system – both at the physiological and neural levels. Patients in this state are hypersensitive to changes occurring both in the body and in their environment. Even when they are asleep, their stress response system at the neural level shows them that they are not safe enough to rest. It is a situation and symptoms analogous to PTSD post-traumatic stress, which often occurs in soldiers and victims of accidents, but in the case of CSF, this trauma has physiological causes, such as a past infection, “Science” who leads the team of Prof. Ute Vollmer-Conna from the University of New South Wales in Sydney.
The team under her leadership examined 30 patients with Chronic Fatigue Syndrome and 40 healthy people. During the research, ECG measurements were also made and the response of the heart and circulatory system to cognitive changes was checked. Patients with CSF did not differ in mating and memory levels from healthy subjects, but it took them much longer to complete each test. Interestingly, before solving the task, they experienced changes in the heartbeat, in extreme cases in the form of slight arrhythmia and a marked reduction in the number of beats. Also, longer after completing each task, their hearts would return to their normal rhythm.
Only the changes in heart rate in these patients were a significant sign of CSF-related cognitive impairment, while fatigue and other fitness measures remained within the normal range during the test.
As prof. Vollmer-Conn, this is the first confirmation that during CSF the body exhibits the features referred to as “System Under Stress” (SUS – System Under Stress) while performing standard tasks, which leads to its rapid exhaustion.
According to the researchers, the next research will focus on finding a constant relationship between slowing the heart rate and CSF attacks and attempts to stabilize the heart rate in patients, which may contribute to reducing the burden of Chronic Fatigue Syndrome. The precedent is the story of one patient with CSF who, thanks to antihypertensive drugs that stabilize heart rhythm, returned to normal activity, exercise and is now one of the few people in Australia who can be said to have had an episode of CSF and is now healthy.
Tekst: Marek Mejssner
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