In this paper, Dr. Shungu et al. found:
(1) elevated lactate in the ventricular cerebrospinal fluid, as they had found earlier,
(2) depletion of glutathione in the occipital cortex, and
(3) decreased regional blood flow in the left anterior cingulate cortex and right lingual regions of the brain, together with a trend in the data suggesting more widespread hypoperfusion in the brain.
I think this is a very significant paper. It appears to provide some support for Marty Pall's NO-ONOO- model, for my Glutathione Depletion--Methylation Cycle Block (GD-MCB) model, and I think also for Ritchie Shoemaker's capillary hypoperfusion model. I must leave it to Prof. Pall and Dr. Shoemaker to comment on how it fits with their models.
As far as the GD-MCB model is concerned, I would say that the results of this study are very consistent with it. To have a direct measurement of glutathione in the brain, and to find that it is depleted, is very supportive of this model.
As with most studies, while it gives us some important data, it also leaves some questions unanswered. As we know, correlation does not show causality. The elevated lactate suggests that the mitochondria are not functioning properly, which has been shown very well for the mitochondria (at least in the neutrophils) by Dr. Sarah Myhill et al. Mito dysfunction is also a component of the GD-MCB model, in which it is proposed that the depletion of glutathione and the concomitant oxidative stress (which can be either a cause or an effect of glutathione depletion, or both) is the first contributor to mitochondrial dysfunction.
Decreased cerebral blood flow has been shown in ME/CFS before, and there are a number of possible contributing causes, some of which are suggested in the GD-MCB model.
One thing that they did not find was evidence of an impact on the ATP supply, which suggests either that the mitochondria were not extremely dysfunctional, or that the deficit in ATP production is being made up for by increased glycolysis, or both. I suspect that the latter is the case, given the observed elevated lactate. Because the brain operates in an isolated manner from the peripheral tissues of the body, I don't think there is a conflict between the Myhill et al. study and this one.