Abnormal cobalamin-dependent transmethylation in AIDS-associated myelopathy

Area of Science:

• Neurology
• Biochemistry
• Infectious Diseases

Background:

• AIDS-associated myelopathy (AM) causes spinal cord white matter vacuolization.
• The exact cause of AM is unknown, but metabolic issues are suspected over direct HIV infection.
• AM shares pathological similarities with vitamin B12 deficiency myelopathy, suggesting a role for the B12-dependent transmethylation pathway.

Purpose of the Study:

• To investigate the role of the vitamin B12-dependent transmethylation pathway in AIDS-associated myelopathy (AM).
• To compare levels of key metabolites in patients with AM, HIV-infected controls, and a healthy reference group.

Main Methods:

• Compared S-adenosyl-methionine (SAM), methionine, homocysteine, and glutathione levels in serum and cerebrospinal fluid (CSF).
• Studied 15 patients with AM, 13 HIV-infected controls without myelopathy (HWM), and a non-HIV-infected control group (NC).
• Ensured all participants had normal vitamin B12, folate, and methylmalonic acid levels.

Main Results:

• CSF SAM levels were significantly lower in the AM group compared to both HWM and NC groups.
• CSF SAM was also lower in the HWM group than in the NC group.
• Serum methionine levels were reduced in the AM group compared to the NC group.

Conclusions:

• AIDS-associated myelopathy (AM) is linked to abnormalities in the vitamin B12-dependent transmethylation pathway.
• Metabolic disturbances, particularly involving SAM, may play a crucial role in AM pathogenesis.