MRS study of the effects of minocycline on markers of neuronal and microglial integrity in ALS.

OBJECTIVE: Magnetic resonance spectroscopy (MRS) allows to monitor brain metabolites noninvasively in amyotrophic lateral sclerosis (ALS). The objective of this study was to use MRS to monitor the effect of minocycline treatment (200 mg/day) over a short period (6 weeks) on the brain metabolites in the precentral gyrus and brainstem in newly diagnosed ALS patients. METHODS: Ten ALS patients (not on riluzole treatment) were recruited and submitted to single-voxel proton MRS longitudinal examinations (1) before minocycline treatment, (2) 3 weeks and (3) 6 weeks after initiation of treatment. RESULTS: Results did not show the expected decrease of N-acetylaspartate/creatine (NAA/Cr) in the precentral gyrus, and an increased NAA/Cr ratio in the brainstem suggested neuronal recovery. The myo-inositol (mI)/Cr ratio was unchanged in the precentral gyrus, but increased in the brainstem, indicating a glial reaction. CONCLUSIONS: MRS results suggest that minocycline treatment could be beneficial in the early stages of ALS.

Chromogranin B P413L variant as risk factor and modifier of disease onset for amyotrophic lateral sclerosis.

Recently, chromogranins were reported to interact specifically with mutant forms of superoxide dismutase that are linked to amyotrophic lateral sclerosis (ALS). This interaction led us to analyze the frequencies of sequence variants of the CHGB gene in ALS patients and matched controls from three different countries. Of particular interest was the finding of the P413L CHGB variant present in 10% of ALS patients (n = 705) as compared to 4.5% in controls (n = 751), conferring a 2.2-fold greater relative risk to develop the disease (P < 0.0001). This effect was mainly contributed by the samples of French origin that yielded a frequency of the P413L variation at 17% in ALS (n = 289) and 5% in controls (n = 448), conferring a 3.3-fold greater risk to develop ALS. Furthermore, the P413L CHGB variant is associated with an earlier age of onset by almost a decade in both sporadic ALS and familial ALS cases. Genetic variation influencing age of onset in ALS had not previously been reported. Expression of fusion CHGB-EGFP constructs in SHSY-5Y cells revealed that the P413L variation can cause defective sorting of CHGB into secretory granules. The finding that CHGB may act as a susceptibility gene and modifier of onset in ALS is consistent with the emerging view that dysfunction of the secretory pathway may contribute to increased vulnerability of motor neurons.