Neurobiological Differences Found in CFS

At the recent IACFS conference, researcher Paul Nestadt described findings from a study of neurometabolites in CFS undertaken by a team of researchers led by Dr. Dikoma Shungu and funded by the CFIDS Association.

In an attempt to understand the neurobiological effects of CFS and to discern potential biomarkers for the illness, these researchers used cross-sectional neuroimaging to compare regional brain metabolite levels and to examine the association of the neurochemical findings with the symptomology of the illness.

Studying metabolites involves looking at the unique chemical fingerprints that specific cellular processes leave behind. In particular this study examined the neurochemicals in the brain and spinal fluid for differences related to CFS and what that might suggest about the illness, particularly compared to disorders with demonstrated symptom overlap such as major depression or anxiety disorders.

Using an MRI technology called proton magnetic resonance spectroscopic imaging (H MSRI), Shungu, Nestadt and their colleagues examined 16 CFS patients, 16 healthy controls and 16 patients with generalized anxiety disorder (GAD)—a condition marked by worry, fatigue and impaired concentration. Regional brain metabolite levels were obtained, including ventricular lactate in cerebrospinal fluid, N-acetyl-aspartate (NAA), total choline-containing compounds and total Creatine (tCR).

What they found was that ventricular lactate levels were significantly elevated in CFS patients compared to GAD patients (297% higher) and healthy controls (348% higher). CFS patients also exhibited significant elevations in NAA to tCr ratios in the occipital hippocampal region of the brain and other chemical variations in other brain regions.

In all three groups, lactate levels positively correlated to levels of fatigue, and within CFS patients, specific neurochemical levels could be correlated to depressive severity.

These preliminary results show that a significant portion of patients diagnosed with CFS have elevated ventricular lactate levels, potentially suggesting anaerobic energy conversion in the brain and/or mitochondrial dysfunction—the mitochondria being the energy conversion “power plant” of a cell.

Findings also clearly support a biologic difference between CFS and neuropsychiatric disorders such as GAD. Additionally, marked differences in hippocampal glutamate appear to distinguish CFS patients with accompanying depression from CFS patients without depression.

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