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Abstract

Objective
To investigate the metabolic and functional status of muscles of fibromyalgia (FM) patients, using P-31 magnetic resonance spectroscopy (MRS).

Methods
Twelve patients with FM and 11 healthy subjects were studied. Clinical status was assessed by questionnaire. Biochemical status of muscle was evaluated with P-31 MRS by determining concentrations of inorganic phosphate (Pi), phosphocreatine (PCr), ATP, and phosphodiesters during rest and exercise. Functional status was evaluated from the PCr/Pi ratio, phosphorylation potential (PP), and total oxidative capacity (Vmax).

Results
Patients with FM reported greater difficulty in performing activities of daily living as well as increased pain, fatigue, and weakness compared with controls. MRS measurements showed that patients had significantly lower than normal PCr and ATP levels (P < 0.004) and PCr/Pi ratios (P < 0.04) in the quadriceps muscles during rest. Values for PP and Vmax also were significantly reduced during rest and exercise.

Conclusion
P-31 MRS provides objective evidence for metabolic abnormalities consistent with weakness and fatigue in patients with FM. Noninvasive P-31 MRS may be useful in assessing clinical status and evaluating the effectiveness of treatment regimens in FM.

Objectives

To evaluate the intracellular levels of the high energy adenosine triphosphate nucleotide ATP and essential divalent cations, calcium and magnesium, in platelets of patients affected by primary fibromyalgia syndrome (FMs).
Design and method

Platelet ATP and cation concentrations were measured in 25 patients affected by FMs and 25 healthy volunteers through a chemiluminescent and a fluorimetric assay, respectively.
Results

Significant lower ATP levels were observed inside platelets of FM patients (fmol ATP/plt: 0.0169 ± 0.0012 vs. healthy controls, fmol ATP/plt: 0.0306 ± 0.0023, mean ± SEM) (low asterisklow asterisklow asteriskP < 0.0001). A trend towards higher calcium concentrations (P = 0.06) together with significant increased magnesium levels were also reported in platelets of patients by comparison with controls (P = 0.02).

Conclusions

This preliminary study suggests that disturbances in the homeostasis of platelet ATP metabolism-signaling and calcium-magnesium flows might have a relevance in the pathogenesis of FMs.

Keywords: Fibromyalgia; Platelets; Adenosine triphosphate; Calcium; Magnesium

ABSTRACT

Objective.—The periaqueductal gray matter (PAG) is at the center of a powerful descending antinociceptive neuronal network. We studied iron homeostasis in the PAG as an indicator of function in patients with episodic migraine (EM) between attacks and patients with chronic daily headache (CDH) during headache. High-resolution magnetic resonance techniques were used to map the transverse relaxation rates R2, R2*, and R2' in the PAG, red nucleus (RN), and substantia nigra (SN). R2' is a measure of non-heme iron in tissues.

Methods.—Seventeen patients diagnosed with EM with and without aura, 17 patients diagnosed with CDH and medication overuse, and 17 normal adults (N) were imaged with a 3.0-tesla magnetic resonance imaging system. For each subject, mean values of the relaxation rates, R2 (1/T2), R2* (1/T2*), and R2' (R2* − R2) were obtained for the PAG, RN, and SN. R2, R2*, and R2' values of the EM, CDH, and N groups were compared using analysis of variance, Student t test, and correlation analysis.

Results.—In the PAG, there was a significant increase in mean R2' and R2* values in both the EM and CDH groups (P<.05) compared with the N group, but no significant difference in these values was demonstrated between the EM and CDH groups, or between those with migraine with or without aura in the EM group. Positive correlations were found for duration of illness with R2' in the EM and CDH groups. A decrease in mean R2' and R2* values also was observed in the RN and SN of the CDH group compared with the N and EM groups (P<.05), explained best by flow activation due to head pain.

Conclusions.—Iron homeostasis in the PAG was selectively, persistently, and progressively impaired in the EM and CDH groups, possibly caused by repeated migraine attacks. These results support and emphasize the role of the PAG as a possible "generator" of migraine attacks, potentially by dysfunctional control of the trigeminovascular nociceptive system.

Contemporary concepts of migraine pathogenesis
K.M. A. Welch

From the Department of Neurology, Finch University of the Health Sciences and the Chicago Medical School, Chicago, Illinois.

The pathogenesis of migraine is incompletely understood. Recent discoveries have shed light on the neuronal events mediating both the aura and the headache phases of migraine, identifying a cerebral cortical origin of migraine aura, susceptibility to attacks based on cortical hyperexcitability, and headache originating in the trigeminovascular system and its central projections. Abnormal modulation of brain nociceptive systems, at first transient but becoming permanent with continuing illness and, predisposing to central sensitization, may explain the prolonged headache of the migraine attack and the shift of the migraine phenotype from episodic to chronic headache. Migraine attacks might also originate in abnormal nociceptive neuromodulator centers in the brainstem.