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The âDreadedâ Muscle Biopsy
The details of our muscle biopsy research are a common source of questions and debate within the investigator group and our wonderful cohort of trekkers. Dan will currently be completing the third biopsy for the investigator group up at Everest Base Camp (in a small number of instances, their 4th biopsy!).
All of the investigators at EBC, the identical twins and 15 of our fantastic Sherpa group have undergone muscle biopsies at sea-level (or Kathmandu in the case of the Sherpas) and EBC. The investigator group have undergone 2, at the beginning and end of their long stint at EBC.
The muscle biopsies have been undertaken by Dan Martin and myself and I was fortunate to be involved with the Sherpa group, both undertaking their biopsies in Kathmandhu and at EBC. I had a wonderful time walking with the 14 Trek A Sherpas from Namche to EBC along with our famous leader, Andre Vercueil. We were joined by Johnny, Chris and Will who had caught us up on their rapid ascent to visit EBC from the XE2 Kathmandhu laboratory.
Laughter, singing and continual surprise will remain forever in my memory when trekking with the Sherpas. I was particularly grateful to Sona Lhamu Sherpa and Ngima Tidikee Sherpa who spoke superb English and were fantastically helpful with all of the group during the laboratory testing at Kathmandu, Namche and EBC.Their reassurance during the muscle biopsies was particularly helpful with Ngima herself volunteering to be the first Sherpa to undergo this investigation. Many of the Sherpas had no previous experience of hospital procedures and to go through this test involved huge trust on their part.
The muscle biopsy technique involves injecting 8ml of strong local anaesthetic into the skin and muscle approximately two thirds of the way down the outer side of the thigh. An incision 8-10mm long is then made through the skin and dissection undertaken through the fat and deep fascial layer to reach the muscle which is known as vastus lateralis, (for those of you with an interest in Latin!) At this point an instrument known as a Tilley Henkel forcep, which was designed for performing an operation on the sphenoid sinus at the back of the nose more than 100 years ago, is then introduced into the muscle of the thigh and 150mg of muscle are removed. This corresponds to a portion of muscle approximately 10x8x4mm. Bleeding is stopped by direct pressure on the thigh and a bandage applied. Additionally everyone is given a supply of significant painkillers for a minimum of 3 days though they may be required for somewhat longer.
The muscle biopsy is then divided carefully into different portions for mitochondrial analysis, part of which was immediately done, at EBC by Andrew Murrayâs team from Cambridge, James Horscroft and Aleksandra Kotwica Click Here. A portion of the muscle goes for mitochondrial metabolomics. This newer metabolic profiling method can give us information on many metabolic pathways in the mitochondria from these tiny samples.
A further portion of the muscle goes for proteomic studies. These involve evaluating the function and structure of proteins and the modifications related to changes in the protein which factors such as hypoxia and critical illness can produce. It is now realized that mRNA is not always translated into protein. The current physiological state of any cell may alter the amount of protein produced for a given amount of mRNA. Proteomics allow a direct measure of the type, quantity and activity pattern of the protein in the cell.
A final portion is used for the study of epigenetics which is an exciting relatively new branch of science studying changes in gene expression or cellular phenotype caused by mechanisms such as environmental factors, rather than changes in the underlying gene sequence. These studies are of particular interest in the identical twins.
As the only surgeon in the group on this particular expedition I have to apologise for undertaking an array of somewhat invasive studies, amongst them muscle biopsies, but I am sure that my colleagues would only expect this to be in keeping with a surgeonâs stereotype! No pain, no gain! Happy biopsying at EBC, Dan.
David Howard
XE2 Investigator
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