Defective cerebral gamma-aminobutyric acid-A receptor density in patients with systemic lupus erythematosus and central nervous system involvement. An observational study

Lupus. 2010 Jul;19(8):918-26. doi: 10.1177/0961203310364398. Epub 2010 Apr 28.

Abstract

Gamma-aminobutyric acid-A (GABA-A) receptors play a crucial role in regulating neuronal excitability and cognitive functions. Single-photon emission computerized tomography (SPECT) analysis of GABA-A receptors binding by (123)I-labelled Iomazenil ((123)I-IMZ) has been applied in some neuropsychiatric disorders to investigate conditions where GABA-A receptor density can be detected in several pathophysiological conditions. In this study we investigate cerebral GABA-A receptor density in a small series of patients with systemic lupus erythematosus (SLE) and cognitive impairment characterized by recurrent, episodic memory loss. Nine female patients with SLE and cognitive alterations underwent to a clinical neuropsychiatric evaluation including digital video-EEG, brain MRI, (99m)Tc-ECD brain SPECT and (123)I-IMZ brain SPECT. All patients tested showed diffuse or focal GABA-A receptor density reduction. This is, to our knowledge, the first report on GABA-A receptor density abnormalities associated with cognitive defects in SLE patients. We hypothesize that in our series a decrease in GABA-A receptor density might be related to the neurological manifestations. Further studies are needed to clarify this aspect and the possible mechanisms. GABA-A receptor density impairment might be due to the SLE-related cerebral vasculopathy, or to neuronal-reacting auto-antibodies or drugs which could interfere with GABA-A receptors expression/binding. This study may support the concept that cognitive impairment in systemic lupus erythematosus could be the outcome of fine-tuned neurotransmission alterations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Central Nervous System / diagnostic imaging*
  • Central Nervous System / metabolism
  • Cerebral Cortex / diagnostic imaging*
  • Cerebral Cortex / metabolism
  • Cerebrovascular Circulation / physiology
  • Cognition Disorders / diagnostic imaging
  • Cognition Disorders / pathology
  • Electroencephalography
  • Female
  • Flumazenil / analogs & derivatives
  • Flumazenil / chemistry
  • Flumazenil / metabolism
  • Humans
  • Iodine Radioisotopes / chemistry
  • Iodine Radioisotopes / metabolism
  • Lupus Erythematosus, Systemic / metabolism
  • Lupus Erythematosus, Systemic / pathology*
  • Magnetic Resonance Imaging
  • Middle Aged
  • Pregnancy
  • Radiopharmaceuticals / metabolism
  • Receptors, GABA-A / genetics
  • Receptors, GABA-A / metabolism*
  • Receptors, GABA-A / ultrastructure*
  • Tomography, Emission-Computed, Single-Photon / methods

Substances

  • Iodine Radioisotopes
  • Radiopharmaceuticals
  • Receptors, GABA-A
  • Flumazenil
  • iomazenil