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A recent study by Alkhunizi et al., Gadolinium Retention in the Central and Peripheral Nervous System: Implications for Pain, Cognition, and Neurogenesis, found that gadolinium was retained, not only in the cerebrum, but also in the spinal cord and peripheral nerves of rats exposed to multiple administrations of linear and macrocyclic agents. Healthy rats were injected daily for 20 days with the linear gadolinium-based contrast agent (GBCA) gadodiamide or the macrocyclic agent gadoterate meglumine. Gadolinium (Gd) retention in the cerebrum, spinal cord, and peripheral nerves occurred with both agents; however, significantly more was retained from the linear agent gadodiamide.
The study also assessed the functional implications of Gd retention on hippocampal neurogenesis and sensory and cognitive processing. In rats, gadodiamide, but not gadoterate meglumine, led to pain hypersensitivity. The authors said their results show that repeat administration of gadodiamide leads to heat and mechanical hyperalgesia in rats, suggesting that the linear GBCA might have triggered the sensitization of spinal cord nociceptive neurons. Neither agent was found to affect spatial working memory performance, hippocampal cellular proliferation, or hippocampal neurogenesis.
Interestingly, the authors commented that “retention of gadolinium in the spinal cord and peripheral nerves might contribute to sensory symptoms and burning pain in the torso and extremities described by some patients after GBCA administration.” They also said, “eventually, attention must be drawn to the long-term effects of such metal retention in the central and peripheral nervous system, especially in children and adults with medical conditions necessitating multiple MRI examinations, such as brain tumors, spinal cord abnormalities, or multiple sclerosis.”
I agree that attention must be drawn to the long-term effects of metal retention in the body, but not eventually, it needs to happen now.
I think this is an important study because the focus is not just on the gadolinium that was retained in brain tissue. While the brain is vital to our survival, it is important to investigate where else it is being retained and to consider what adverse effects that might have on the human body. In the study by Alkhunizi et al., the results show that Gd retained in the spinal cord and peripheral nervous system can adversely affect nociceptive neurons. According to Krames (2014), nociceptive pain is the most common type of pain and results from signaling of noxious or potentially harmful stimuli by nociceptors around the body. Could that explain many of the neuropathic symptoms that patients have described after their MRIs with a gadolinium-based contrast agent?
Alkhunizi, S. M., Fakhoury, M., Abou-Kheir, W., & Lawand, N. (2020). Gadolinium Retention in the Central and Peripheral Nervous System: Implications for Pain, Cognition, and Neurogenesis. Radiology, 192645. https://doi.org/10.1148/radiol.2020192645
Krames, E. S. (2014). The Role of the Dorsal Root Ganglion in the Development of Neuropathic Pain. Pain Medicine, 15(10), 1669–1685. https://doi.org/10.1111/pme.12413