Metabolite concentrations in the anterior cingulate cortex predict high neuropathic pain impact after spinal cord injury

Pain, 2013 · DOI: 10.1016/j.pain.2012.07.022 · Published: February 1, 2013

Spinal Cord Injury Pain Management Medical Imaging

Simple Explanation

Persistent pain after spinal cord injury (SCI) reduces quality of life. This study explores biomarkers of neuropathic pain to understand its mechanisms. The research focuses on the anterior cingulate cortex (ACC), a brain area involved in pain and emotional processing. Using magnetic resonance spectroscopy (MRS), the researchers measured metabolite concentrations in the ACC of individuals with SCI and varying levels of neuropathic pain. They compared these measurements with those of able-bodied, pain-free control subjects. The study found that severe neuropathic pain with psychosocial impact is linked to specific metabolite concentrations in the ACC, suggesting neuronal and/or glial dysfunction. These findings indicate potential biomarkers for severe SCI-related neuropathic pain.

Study Duration

Not specified

Participants

Participants with SCI and neuropathic pain (n = 50), SCI without neuropathic pain (n = 18), and able-bodied, pain-free control subjects (n = 24)

Evidence Level

Not specified

Key Findings

1
The SCI-HPI group had significantly higher levels of myoinositol (Ins), creatine, and choline, and significantly lower levels of N-acetyl aspartate/Ins and glutamate-glutamine (Glx)/Ins ratios than the SCI-LPI group.
2
The lower Glx/Ins ratio significantly discriminated between SCI-HPI and the A-B and SCI-noNP groups, displayed excellent test-retest reliability, and was significantly related to greater pain severity, interference, and affective distress.
3
The combination of lower glutamatergic metabolism and proliferation of glia and glial activation are underlying mechanisms contributing to the maintenance of severe neuropathic pain with significant psychosocial impact in chronic SCI.

Research Summary

This study investigated the relationship between metabolite concentrations in the anterior cingulate cortex (ACC) and neuropathic pain after spinal cord injury (SCI). The study revealed that individuals with severe neuropathic pain and high psychosocial impact (SCI-HPI) had distinct metabolite profiles in the ACC compared to those with low pain impact (SCI-LPI), SCI without neuropathic pain (SCI-noNP), and able-bodied controls (A-B). The Glx/Ins ratio emerged as a potential biomarker for severe SCI-related neuropathic pain with significant psychosocial impact, showing significant correlations with pain severity, life interference, and affective distress.

Practical Implications

Biomarker Identification

The Glx/Ins ratio may serve as a useful biomarker for identifying individuals with severe SCI-related neuropathic pain and significant psychosocial impact, aiding in diagnosis and treatment planning.

Targeted Therapies

Understanding the underlying mechanisms of neuropathic pain, such as lower glutamatergic metabolism and glial activation, may lead to the development of targeted therapies to alleviate pain and improve quality of life.

Personalized Treatment

Assessment of ACC metabolite concentrations could contribute to personalized treatment approaches, tailoring interventions based on individual neurochemical profiles to optimize pain management strategies.

Study Limitations

1
The complexity of pain after SCI in combination with the injury itself may confound the findings.
2
ACC Ins concentrations by themselves are not useful in differentiating subjects with neuropathic pain from those with no pain.
3
The present study excluded participants with moderate to major depression, which may limit the generalizability of our findings.

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