Journal of IiME Volume 2 Issue 1 www.investinme.org WHO GETS ME AND WHY - The role of impaired capillary blood flow in ME (continued) BLOOD FILTERABILITY AND RED CELL SHAPE The findings of reduced blood filterability stimulated the thought that some change in the surface features of red cells might be involved (in the terms of Weed’s concept). To explore this possibility, a technique used for the rapid examination of theatre specimens by electron microscopy was adapted to study red cell morphology. The key factor was that the blood samples (3 to 5 drops of venous blood) were fixed immediately by being added to 5ml of 2.5% glutaraldehyde in 0.1M cacodylate buffer at pH 7.4. After fixation for overnight, at least, the cells were dehydrated in ascending concentrations of ethanol to absolute, then passed through three changes of pure, dry acetone. A drop of the acetone-suspended red cells was placed on a glass cover slip fixed to an aluminium stub with double sided adhesive tape. After air-drying, the cells were gold-coated in a sputter coater, then photographed under standard conditions in a scanning electron microscope. The cells in the resulting micrographs were classified into six different shape classes and the proportions expressed as percentages of the total number of cells counted. The first series of blood samples assessed in this way came from healthy blood donors, and from the first sample it was clear that the current teaching that all red cells were biconcave discocytes was not sustainable. In 1989 I was able to report that the red cells in immediately fixed blood samples from healthy animals and humans could be classified into six different shape classes.(7) Later in the year I reported that blood samples from patients with acute ME showed increased proportions of cup forms (stomatocytes), a form which is known to be poorly deformable. (8) At a meeting in India in 1992, I discussed the red cell shape changes which had been found in six chronic disorders. (9) Studies of the relevant literature, while preparing those reports, revealed that there had been earlier reports concerning changes in the shape populations of red cells. From 1974-78, there had been several reports concerning red cell shape in patients with muscular dystrophy. However, only one study (10) used immediately fixed blood samples, and the results were different from those studies which had manipulated the blood cells prior to fixation. The authors (10) noted that they were unable to prevent unfixed red cells from changing shape, even in their native plasma in a refrigerator. This is the expected response of red cells to a changing environment. In 1977, it was reported that patients with Huntington’s Disease had increased proportions of stomatocytes (cup forms). (11) Because increased proportions of stomatocytes would have an adverse effect on capillary blood flow, it is of interest that a 1985 study reported impairment of cerebral blood flow which Invest in ME (Charity Nr. 1114035) was shown to correlate with cognitive impairment of patients with Huntington’s Disease.(12) Even though it was very likely that stomatocytes were responsible for the impaired cerebral blood flow, no reference was made to the 1977 study. In general there was no clinical interest in changed shape populations of red cells, and such reports provoked little continuing interest. However, Mukherjee et al (13) were stimulated by our 1986 study of poorly filterable blood, to embark on a study of red cell morphology in ME people. They reported the presence of small numbers of grossly abnormal red cells. But the cells examined had been washed and centrifuged prior to fixation, and it is very likely that the abnormal cells were a result of the preparation technique. In the 13,000-odd immediately fixed blood samples relating to a number of chronic conditions in eight countries, which I have assessed, I have never seen a cell with the features of that described by Mukherjee et al. At the Cambridge Symposium on ME in 1990, I reported that blood samples from another 99 patients with acute ME showed similar values for increased cup forms to those of the previously reported 102 cases (14). It was noted also that there were small numbers of cases which presented with increased proportions of flat cells or cells with altered margins. In hindsight, it now seems likely that those changes were the beginning of a trend to chronic ME, as by 1992 only about 5% of cases were presenting with the cup forms of acute ME, and increased flat cells was the most common feature of chronic ME. It should be noted that the title of the paper I submitted made no mention of chronic fatigue syndrome, and this was added to the title by the editors, without discussion. Thus, the information relating to reduced blood filterability is reinforced and possibly explained by the changed red cell morphology seen by scanning electron microscopy, so impaired capillary blood flow can be expected. What is important is that change in the cell shape populations is not a benign event. Remember, for example, that Weed (5) had noted that the deformability of red cells depended upon, “…maintenance of the biconcave shape.” Possibly of greater physiological importance were the findings of Vandergriff and Olson (15) that red cell shape was a determinant of the rate of uptake and release of oxygen. margins) were found to have a 45% reduction in the uptake of oxygen and a 23% reduction in release rate. TIREDNESS, MUSCLE DYSFUNCTION AND CAPILLARY BLOOD FLOW It is particularly unfortunate that the term ‘fatigue’ is used so frequently in the ME literature. Both Funk and (Continued on page 28) Page 27/34 For example, crenated cells (cells with altered
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